diff --git a/internal/agent/reseat.go b/internal/agent/reseat.go
index c52ce902..43c9b8c9 100644
--- a/internal/agent/reseat.go
+++ b/internal/agent/reseat.go
@@ -142,7 +142,7 @@ func sameModel(opts []Option, ref string) Option {
 			if o.Ref == "" || strings.HasPrefix(o.Ref, provider.GroupPrefix) || !served(o.Ref) {
 				continue
 			}
-			if _, m, _ := strings.Cut(o.Ref, "/"); provider.AutoGroupID(m) == gid {
+			if pid, m, _ := strings.Cut(o.Ref, "/"); provider.AutoGroupOf(pid, m) == gid {
 				return o
 			}
 		}
diff --git a/internal/gui/assets/app.css b/internal/gui/assets/app.css
index 6cfd358e..055194cb 100644
--- a/internal/gui/assets/app.css
+++ b/internal/gui/assets/app.css
@@ -2019,6 +2019,9 @@ body.window .ag-sk-icon { width: 22px; height: 22px; border-radius: 6px; }
 .mname .mwho input { flex: 1; min-width: 0; max-width: 220px; height: 25px; }
 .mname .mwho code { font-size: 11px; color: var(--muted); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; min-width: 0; }
 .mname .mapi { flex: none; height: 24px; font-size: 11px; }
+.mname .msame { display: flex; align-items: center; gap: 6px; flex: 0 1 230px; min-width: 0; font-size: 11.5px; color: var(--muted); }
+.mname .msame span { flex: none; }
+.mname .msame input { flex: 1; min-width: 0; height: 25px; font-size: 11.5px; }
 .mname .mlevels { display: flex; flex-wrap: wrap; gap: 2px 10px; font-size: 11.5px; }
 .editor .mname label.tick { gap: 4px; }
 .mname .text { flex: none; padding: 2px 7px; font-size: 11.5px; }
diff --git a/internal/gui/assets/app.js b/internal/gui/assets/app.js
index 5b69f2fa..0384c983 100644
--- a/internal/gui/assets/app.js
+++ b/internal/gui/assets/app.js
@@ -6243,6 +6243,24 @@ function renderModels(p) {
       const who = el("div", "mwho");
       who.append(name, el("code", "", m.id));
       row.append(who);
+      // the model of other providers' it is, for the routing groups magpie
+      // finds, when its id is one no rule matches up with theirs
+      // (Volcengine's deepseek-v4-1-flash-260910 and others'
+      // deepseek-v4.1-flash, #583); empty merges it by its own id, which
+      // the box shows as it is merged
+      const sameNow = () => prefs[id]?.same ?? m.same ?? "";
+      const sameBox = el("label", "msame");
+      const same = input(sameNow(), m.merge || m.id);
+      same.title = t("The model other providers serve that {id} is the same as: the routing groups magpie finds put them together. Empty: by its own id", { id: m.id });
+      same.spellcheck = false;
+      same.onchange = () => {
+        const v = same.value.trim();
+        if (v === (m.same || "")) delete pref().same; else pref().same = v;
+        drawReset();
+      };
+      same.onkeydown = (e) => { e.stopPropagation(); if (e.key === "Enter") same.blur(); else if (e.key === "Escape") { same.value = sameNow(); same.blur(); } };
+      sameBox.append(el("span", "", t("Same as")), same);
+      row.append(sameBox);
       const [img, imgCb] = tick(t("Accepts images"), imagesNow());
       img.title = t("Whether agents are told {id} can see images", { id: m.id });
       imgCb.onchange = () => {
@@ -6297,7 +6315,7 @@ function renderModels(p) {
       const unsaved = el("span", "hint munsaved", t("unsaved"));
       unsaved.title = t("Made when the provider is saved; Cancel drops it");
       const reset = el("button", "text action", t("Restore default"));
-      reset.title = t("Its own name, every reasoning level it has, whether it sees images, and the API it is asked on");
+      reset.title = t("Its own name, every reasoning level it has, whether it sees images, the API it is asked on, and the model it is the same as");
       reset.onclick = () => {
         prefs[id] = {};
         if (m.default) prefs[id].name = "";
@@ -6307,6 +6325,8 @@ function renderModels(p) {
         imgCb.checked = imagesNow();
         for (const [l, cb] of boxes) cb.checked = keptNow().includes(l);
         if (m.api) prefs[id].api = "";
+        if (m.same) prefs[id].same = "";
+        same.value = sameNow();
         if (apiSeg) { for (const b of apiSeg.querySelectorAll(".opt")) b.classList.toggle("on", b.dataset.api === apiNow()); slide(apiSeg, "api"); }
         drawReset();
       };
@@ -6316,7 +6336,7 @@ function renderModels(p) {
         unsaved.hidden = !prefs[id];
         // staged back to its own already, there is nothing to restore
         const images = prefs[id]?.ownImages ? false : prefs[id]?.images !== undefined ? prefs[id].images !== !!m.ownImages : !!m.imageSet;
-        const custom = nameNow() !== "" || (prefs[id]?.efforts ? prefs[id].efforts.length > 0 : !!m.kept?.length) || images || apiNow() !== "";
+        const custom = nameNow() !== "" || (prefs[id]?.efforts ? prefs[id].efforts.length > 0 : !!m.kept?.length) || images || apiNow() !== "" || sameNow() !== "";
         reset.hidden = !custom;
       };
       row.append(unsaved, reset);
diff --git a/internal/gui/assets/i18n.js b/internal/gui/assets/i18n.js
index e84b75cb..6f410e54 100644
--- a/internal/gui/assets/i18n.js
+++ b/internal/gui/assets/i18n.js
@@ -903,7 +903,9 @@ const I18N = {
     "Keep at least one level": "至少保留一个档位",
     "{id}: {levels}": "{id}：{levels}",
     "Restore default": "恢复默认",
-    "Its own name, every reasoning level it has, whether it sees images, and the API it is asked on": "恢复默认名称、全部推理档位、是否支持图片，以及请求所用的协议",
+    "Its own name, every reasoning level it has, whether it sees images, the API it is asked on, and the model it is the same as": "恢复默认名称、全部推理档位、是否支持图片、请求所用的协议，以及它等同的模型",
+    "Same as": "等同于",
+    "The model other providers serve that {id} is the same as: the routing groups magpie finds put them together. Empty: by its own id": "{id} 与其他供应商的哪个模型是同一个：magpie 自动发现的路由分组会把它们合并在一起。留空则按它自己的 ID 合并",
     "The API {id} is asked on. Auto: as the vendor's list says, else each URL the provider has; pick one when the vendor serves it on that one only": "{id} 请求所用的协议。自动：按供应商模型列表所说，否则依次用供应商已填的各个地址；供应商只在某个协议上提供它时，选那一个",
     "{id} is as its provider has it again": "{id} 已恢复为供应商的默认设置",
     "unsaved": "未保存",
diff --git a/internal/gui/providers.go b/internal/gui/providers.go
index 62fe4b50..0816f07d 100644
--- a/internal/gui/providers.go
+++ b/internal/gui/providers.go
@@ -40,6 +40,8 @@ type modelJSON struct {
 	Rate     float64  `json:"rate,omitempty"`    // the credits a request costs the subscription, as a multiple
 	RateWas  float64  `json:"rateWas,omitempty"` // the rate before a discount running now
 	API      string   `json:"api,omitempty"`     // the one API the user said it is asked on
+	Same     string   `json:"same,omitempty"`    // the model the user said it is the same as, for the groups magpie finds (#583)
+	Merge    string   `json:"merge,omitempty"`   // what those groups merge it by when the user says nothing
 }
 
 type providerJSON struct {
@@ -376,6 +378,7 @@ func providerInfo(p provider.Provider, agents []agentUse) providerJSON {
 	}
 	seen := map[string]bool{}
 	names, kept := p.ModelNames(), p.ModelEfforts()
+	sames := settings.Load().ModelSameAs
 	// a list fetched before magpie kept each model's most: the one Codex
 	// CLI keeps says it
 	var most []catalog.Model
@@ -401,6 +404,8 @@ func providerInfo(p provider.Provider, agents []agentUse) providerJSON {
 		if api, ok := p.ModelAPI(m.ID); ok {
 			j.API = string(api)
 		}
+		j.Same = sames[p.ID+"/"+m.ID]
+		j.Merge = provider.MergeName(m.ID)
 		if len(j.Efforts) == 0 {
 			j.Efforts, j.Given = provider.Levels, true
 		}
diff --git a/internal/gui/providers_modelprefs_test.go b/internal/gui/providers_modelprefs_test.go
index 3dcadac1..017f0660 100644
--- a/internal/gui/providers_modelprefs_test.go
+++ b/internal/gui/providers_modelprefs_test.go
@@ -38,6 +38,13 @@ func TestProviderSaveModelPrefs(t *testing.T) {
 	if s.ModelNames["relay/sol"] != "My Sol" || !slices.Equal(s.ModelEfforts["relay/sol"], []string{"low", "high"}) || !s.ModelImages["relay/sol"] {
 		t.Fatalf("names %v, efforts %v, images %v", s.ModelNames, s.ModelEfforts, s.ModelImages)
 	}
+	// the model it is the same as, for the groups magpie finds (#583)
+	if w := post(`{"id":"relay","from":"relay","name":"Relay","chat":"http://127.0.0.1:1/v1","models":["sol"],"modelPrefs":{"sol":{"same":"deepseek-v4.1-flash"}}}`); w.Code != 200 {
+		t.Fatalf("%d %s", w.Code, w.Body)
+	}
+	if got := settings.Load().ModelSameAs["relay/sol"]; got != "deepseek-v4.1-flash" {
+		t.Fatalf("same as %q", got)
+	}
 	// one it refuses fails the Save, saying why
 	if w := post(`{"id":"relay","from":"relay","name":"Relay","chat":"http://127.0.0.1:1/v1","models":["sol"],"modelPrefs":{"sol":{"efforts":["loud"]}}}`); w.Code == 200 || !strings.Contains(w.Body.String(), "loud") {
 		t.Fatalf("%d %s", w.Code, w.Body)
diff --git a/internal/gui/settings_keep_test.go b/internal/gui/settings_keep_test.go
index b6dac650..00b0a700 100644
--- a/internal/gui/settings_keep_test.go
+++ b/internal/gui/settings_keep_test.go
@@ -78,6 +78,7 @@ func TestSettingsSaveKeepsWhatItDoesNotSend(t *testing.T) {
 		ModelPrices:         map[string]settings.ModelPrice{"p/m": {Input: &one, Output: &two}},
 		ModelWires:          map[string]string{"p/m": "vendor-c/m"},
 		ModelAPIs:           map[string]string{"p/m": "anthropic"},
+		ModelSameAs:         map[string]string{"p/m": "deepseek-v4.1-flash"},
 		RedactRules:         []redact.Rule{{Kind: "prefix", Prefix: "oc_sk_"}},
 		LAN:                 true,
 		LANKey:              "sk-lan",
diff --git a/internal/gui/tests/provider-detect.test.cjs b/internal/gui/tests/provider-detect.test.cjs
index 26028181..745382b9 100644
--- a/internal/gui/tests/provider-detect.test.cjs
+++ b/internal/gui/tests/provider-detect.test.cjs
@@ -150,7 +150,7 @@ for (const engine of (process.env.BROWSER ? [process.env.BROWSER] : ["chromium",
         "Taken · save to keep", "Ask {model} on {api} only", "Staged in Names & levels and made with the Save; Auto there gives it back", "{model} is asked on {api} once saved",
         "no URL to ask", "no model to try: type one the vendor serves", "no key is on for this endpoint",
         "The API {id} is asked on. Auto: as the vendor's list says, else each URL the provider has; pick one when the vendor serves it on that one only",
-        "Its own name, every reasoning level it has, whether it sees images, and the API it is asked on",
+        "Its own name, every reasoning level it has, whether it sees images, the API it is asked on, and the model it is the same as",
       ].filter((k) => !I18N.zh[k]));
       assert.deepEqual(missing, [], "every string has its Chinese");
       assert.deepEqual(errors, []);
diff --git a/internal/gui/tests/provider-same-as.test.cjs b/internal/gui/tests/provider-same-as.test.cjs
new file mode 100644
index 00000000..7ad2bf81
--- /dev/null
+++ b/internal/gui/tests/provider-same-as.test.cjs
@@ -0,0 +1,99 @@
+// A model a vendor names its own way (Volcengine Ark's
+// deepseek-v4-1-flash-260910) can be said, in the provider editor's Names &
+// levels, to be the same as another vendor's model, so the routing groups
+// magpie finds merge them (kyzhouxu, #583). It is staged and made with the
+// editor's Save, as the rest of Names & levels is; Cancel drops it.
+const assert = require("node:assert/strict");
+const fs = require("node:fs/promises");
+const path = require("node:path");
+const { test } = require("node:test");
+const { chromium, webkit } = require("playwright");
+
+const assets = path.resolve(__dirname, "../assets");
+const levels = ["none", "low", "medium", "high"];
+
+function serve(lang, posts) {
+  const state = { agents: [], profiles: [], settings: { lang, theme: "light" } };
+  const models = [
+    { id: "deepseek-v4-1-flash-260910", name: "deepseek-v4-1-flash-260910", on: true, efforts: levels, images: false, merge: "deepseek-v4-1-flash" },
+    { id: "ep-2026-sol", name: "ep-2026-sol", on: true, efforts: levels, images: false, merge: "ep-2026-sol", same: "sol" },
+  ];
+  const provider = { id: "relay", name: "Relay", icon: "generic", chat: "https://relay.example/v1", responses: "", anthropic: "", models, agents: [], key: { set: true, masked: "sk-…1234" }, ready: true };
+  const providers = { providers: [provider], presets: [], excluded: [], gateway: { running: true, window: true } };
+  return async (route) => {
+    const url = new URL(route.request().url());
+    const json = (data) => route.fulfill({ json: data });
+    if (url.pathname === "/boot.js") return route.fulfill({ contentType: "text/javascript", body: `window.bootPrefs = {lang:${JSON.stringify(lang)},theme:"light",web:true};` });
+    if (url.pathname === "/wails/runtime.js") return route.fulfill({ contentType: "text/javascript", body: "export const Window = {};" });
+    if (url.pathname === "/api/state") return json(state);
+    if (url.pathname === "/api/providers") return json(providers);
+    if (url.pathname === "/api/groups") return json({ groups: [] });
+    if (url.pathname.startsWith("/api/provider/")) {
+      posts.push({ path: url.pathname, body: route.request().postDataJSON() });
+      return json(providers);
+    }
+    if (url.pathname.startsWith("/api/")) return json({});
+    const file = path.join(assets, url.pathname === "/" ? "index.html" : url.pathname);
+    await route.fulfill({ body: await fs.readFile(file), contentType: { ".html": "text/html", ".js": "text/javascript", ".css": "text/css", ".svg": "image/svg+xml", ".png": "image/png" }[path.extname(file)] });
+  };
+}
+
+for (const engine of (process.env.BROWSER ? [process.env.BROWSER] : ["chromium", "webkit"])) {
+  for (const lang of ["en", "zh"]) {
+    test(`${engine} ${lang}: the model a model is the same as is staged and made with the provider's Save`, async (t) => {
+      const browser = await (engine === "webkit" ? webkit.launch() : chromium.launch({ channel: process.env.PLAYWRIGHT_CHANNEL || "chromium" }));
+      t.after(() => browser.close());
+      const page = await (await browser.newContext({ viewport: { width: 900, height: 720 }, reducedMotion: "reduce" })).newPage();
+      page.setDefaultTimeout(5000);
+      const errors = [], posts = [];
+      page.on("pageerror", (e) => errors.push(e.message));
+      await page.route("**/*", serve(lang, posts));
+      await page.goto("http://magpie.test/?view=providers");
+      const zh = lang === "zh";
+      const L = { names: zh ? "名称与推理档位" : "Names & levels", same: zh ? "等同于" : "Same as", unsaved: zh ? "未保存" : "unsaved", save: zh ? "保存" : "Save", cancel: zh ? "取消" : "Cancel", reset: zh ? "恢复默认" : "Restore default" };
+      const open = async () => {
+        await page.locator(".row.provider").click();
+        if (!(await page.locator(".mnames:not([hidden])").count())) await page.getByRole("button", { name: L.names, exact: true }).click();
+      };
+      const row = (id) => page.locator(".mname", { has: page.locator("code", { hasText: id }) });
+      const box = (id) => row(id).getByRole("textbox", { name: L.same, exact: true });
+      await open();
+      // empty, it says what the found groups merge it by now; one given shows
+      assert.equal(await box("deepseek-v4-1-flash-260910").inputValue(), "");
+      assert.equal(await box("deepseek-v4-1-flash-260910").getAttribute("placeholder"), "deepseek-v4-1-flash");
+      assert.equal(await box("ep-2026-sol").inputValue(), "sol");
+      const list = await page.locator(".mnames:not([hidden])").elementHandle();
+      const y = await page.evaluate(() => scrollY);
+      await box("deepseek-v4-1-flash-260910").fill("deepseek-v4.1-flash");
+      await box("deepseek-v4-1-flash-260910").press("Enter");
+      await row("ep-2026-sol").getByRole("button", { name: L.reset }).click();
+      await page.waitForTimeout(200);
+      assert.deepEqual(posts, [], "nothing is sent before the Save");
+      assert(await list.evaluate((e) => e.isConnected), "the list is not redrawn");
+      assert.equal(await page.evaluate(() => scrollY), y, "nothing scrolls the page");
+      assert.equal(await box("ep-2026-sol").inputValue(), "", "Restore default empties it");
+      for (const id of ["deepseek-v4-1-flash-260910", "ep-2026-sol"]) assert(await row(id).getByText(L.unsaved, { exact: true }).isVisible(), id + " says it is unsaved");
+      // Cancel drops them
+      await page.getByRole("button", { name: L.cancel, exact: true }).click();
+      await open();
+      assert.equal(await box("deepseek-v4-1-flash-260910").inputValue(), "");
+      assert.equal(await box("ep-2026-sol").inputValue(), "sol");
+      assert.deepEqual(posts, []);
+      // given again and saved: one Save carries them
+      await box("deepseek-v4-1-flash-260910").fill("deepseek-v4.1-flash");
+      await box("deepseek-v4-1-flash-260910").press("Enter");
+      await box("ep-2026-sol").fill("");
+      await box("ep-2026-sol").press("Enter");
+      await page.getByRole("button", { name: L.save, exact: true }).click();
+      await page.waitForFunction(() => !document.querySelector(".mnames"));
+      assert.deepEqual(posts.map((p) => p.path), ["/api/provider/save"]);
+      assert.deepEqual(posts[0].body.modelPrefs, { "deepseek-v4-1-flash-260910": { same: "deepseek-v4.1-flash" }, "ep-2026-sol": { same: "" } });
+      const missing = await page.evaluate(() => ["Same as",
+        "The model other providers serve that {id} is the same as: the routing groups magpie finds put them together. Empty: by its own id",
+        "Its own name, every reasoning level it has, whether it sees images, the API it is asked on, and the model it is the same as",
+      ].filter((k) => !I18N.zh[k]));
+      assert.deepEqual(missing, [], "every string has its Chinese");
+      assert.deepEqual(errors, []);
+    });
+  }
+}
diff --git a/internal/provider/group.go b/internal/provider/group.go
index 84373e4a..63366696 100644
--- a/internal/provider/group.go
+++ b/internal/provider/group.go
@@ -10,7 +10,9 @@ package provider
 // its own: a model more than one provider serves under the same name is a
 // group of those, derived each time and never stored until the user
 // changes one. Models of different names are only ever grouped by the
-// user: nothing here guesses which models are alike.
+// user — in a group of their own, or by saying in a provider's Names &
+// levels that one is the same as another (settings' ModelSameAs): nothing
+// here guesses which models are alike beyond how vendors spell one id.
 //
 // A group's member may be another group ("group/<id>"): to the group it is
 // one member, which a rule can put first like a model; its models are its
@@ -23,6 +25,8 @@ import (
 	"fmt"
 	"slices"
 	"strings"
+
+	"github.com/yetone/magpie/internal/settings"
 )
 
 // GroupPrefix starts a group's id in the catalog: "group/<id>".
@@ -198,7 +202,7 @@ func groupsIn(entries []Entry) []Group {
 	if f.NoAutoGroups {
 		return out
 	}
-	for _, g := range autoGroups(entries) {
+	for _, g := range autoGroups(entries, settings.Load().ModelSameAs) {
 		if slices.ContainsFunc(out, func(o Group) bool { return o.ID == g.ID }) {
 			continue // the user changed it: theirs now
 		}
@@ -261,6 +265,27 @@ func SetAutoGroups(on bool) error {
 // vendor spells it: "auto-claude-opus-5-5" for claude-opus-5.5.
 func AutoGroupID(model string) string { return "auto-" + Slug(sameModel(model)) }
 
+// AutoGroupOf is the id of the group magpie finds for a provider's model:
+// AutoGroupID of the model the user said it is the same as (settings'
+// ModelSameAs), else of its own id.
+func AutoGroupOf(pid, model string) string {
+	return "auto-" + Slug(mergeKey(pid, model, settings.Load().ModelSameAs))
+}
+
+// MergeName is the name the groups magpie finds merge a model by, when
+// the user said nothing of it: its id as vendors agree on it (sameModel).
+func MergeName(model string) string { return sameModel(model) }
+
+// mergeKey is what the groups magpie finds merge pid's model by: the
+// model the user said it is the same as (same, by "<provider>/<model>"),
+// spelt as vendors agree on it, else its own id so spelt.
+func mergeKey(pid, model string, same map[string]string) string {
+	if v := same[pid+"/"+model]; v != "" {
+		return sameModel(v)
+	}
+	return sameModel(model)
+}
+
 // AutoStandIn is the model a request for a group magpie found goes to while
 // such groups are off (SetAutoGroups): its model, from the first provider
 // that serves it, as "provider/model". An agent set to the group, or a
@@ -276,7 +301,7 @@ func AutoStandIn(id string) (string, bool) {
 		return "", false
 	}
 	for _, e := range entries {
-		if AutoGroupID(e.Model) == gid {
+		if AutoGroupOf(e.Provider.ID, e.Model) == gid {
 			return e.ID, true
 		}
 	}
@@ -284,13 +309,14 @@ func AutoStandIn(id string) (string, bool) {
 }
 
 // autoGroups are the models more than one ready provider serves under the
-// same name — however each vendor spells it (see sameModel) — in the order
-// the providers were added.
-func autoGroups(entries []Entry) []Group {
+// same name — however each vendor spells it (see sameModel), or as the
+// user said one is the same as another (same: settings' ModelSameAs) — in
+// the order the providers were added.
+func autoGroups(entries []Entry, same map[string]string) []Group {
 	var order []string
 	by := map[string][]Entry{}
 	for _, e := range entries {
-		k := sameModel(e.Model)
+		k := mergeKey(e.Provider.ID, e.Model, same)
 		if !slices.ContainsFunc(by[k], func(o Entry) bool { return o.Provider.ID == e.Provider.ID }) {
 			if by[k] == nil {
 				order = append(order, k)
@@ -324,28 +350,52 @@ func autoGroups(entries []Entry) []Group {
 }
 
 // sameModel is a model's name as vendors agree on it: lowercase, without
-// the vendor's own prefix ("anthropic/claude-sonnet-5" is claude-sonnet-5),
-// with a version's dot as Anthropic writes it ("claude-opus-5.5" is
-// claude-opus-5-5) and without the snapshot date some add
-// ("claude-opus-5-5-20260801"). A variant after ":" (":batch") stays apart.
+// the vendor's own prefix ("anthropic/claude-sonnet-5" is claude-sonnet-5,
+// "accounts/fireworks/models/…" too), with a version's dot as Anthropic
+// writes it ("claude-opus-5.5" is claude-opus-5-5, and so is Fireworks'
+// "p" for the dot, "deepseek-v4p1"), "_" as "-", and without the snapshot
+// date some add: "claude-opus-5-5-20260801", Vertex's "…@20260801", and
+// Volcengine Ark's six digits ("deepseek-v4-1-flash-260910" is
+// deepseek-v4-1-flash, #583). Anything else stays: a variant after ":"
+// (":batch"), -flash, -thinking, and a four-digit release (qwen's -2507,
+// kimi-k2-0905) that is a model of its own.
 func sameModel(id string) string {
-	k := strings.ToLower(id)
+	k := strings.ReplaceAll(strings.ToLower(strings.TrimSpace(id)), "_", "-")
 	if i := strings.LastIndex(k, "/"); i >= 0 {
 		k = k[i+1:]
 	}
 	b := []byte(k)
 	for i := 1; i+1 < len(b); i++ {
-		if b[i] == '.' && isDigit(b[i-1]) && isDigit(b[i+1]) {
+		if (b[i] == '.' || b[i] == 'p') && isDigit(b[i-1]) && isDigit(b[i+1]) {
 			b[i] = '-'
 		}
 	}
 	k = string(b)
-	if i := strings.LastIndex(k, "-"); i > 0 && len(k)-i-1 == 8 && strings.HasPrefix(k[i+1:], "20") && strings.Trim(k[i+1:], "0123456789") == "" {
+	if i := strings.LastIndexAny(k, "-@"); i > 0 && snapshotDate(k[i+1:]) {
 		k = k[:i]
 	}
 	return k
 }
 
+// snapshotDate is whether s is the date a vendor dates a snapshot of a
+// model by: YYYYMMDD from 2000 on, or Ark's YYMMDD from 2023 on, with a
+// month and a day that are one.
+func snapshotDate(s string) bool {
+	if strings.Trim(s, "0123456789") != "" {
+		return false
+	}
+	switch {
+	case len(s) == 8 && strings.HasPrefix(s, "20"):
+		return true
+	case len(s) == 6:
+		yy, mm, dd := atoi2(s[0:2]), atoi2(s[2:4]), atoi2(s[4:6])
+		return yy >= 23 && yy <= 39 && mm >= 1 && mm <= 12 && dd >= 1 && dd <= 31
+	}
+	return false
+}
+
+func atoi2(s string) int { return int(s[0]-'0')*10 + int(s[1]-'0') }
+
 func isDigit(c byte) bool { return c >= '0' && c <= '9' }
 
 // FindGroup looks a group up by its catalog id ("group/<id>") and resolves
@@ -765,7 +815,7 @@ func DeleteGroup(id string) error {
 		}
 		return false
 	})
-	if slices.ContainsFunc(autoGroups(providerEntries()), func(g Group) bool { return g.ID == id }) {
+	if slices.ContainsFunc(autoGroups(providerEntries(), settings.Load().ModelSameAs), func(g Group) bool { return g.ID == id }) {
 		f.Groups = append(f.Groups, Group{ID: id, Hidden: true})
 		found = true
 	}
@@ -824,7 +874,7 @@ func RenameGroup(from, to string) error {
 		slices.ContainsFunc(f.Groups, func(o Group) bool { return o.ID == to }) {
 		return fmt.Errorf("there is a group %q already", to)
 	}
-	found := slices.ContainsFunc(autoGroups(providerEntries()), func(o Group) bool { return o.ID == from })
+	found := slices.ContainsFunc(autoGroups(providerEntries(), settings.Load().ModelSameAs), func(o Group) bool { return o.ID == from })
 	g.ID, g.Auto, g.Hidden = to, false, false
 	f.Groups = slices.DeleteFunc(f.Groups, func(o Group) bool { return o.ID == from })
 	if found {
diff --git a/internal/provider/group_test.go b/internal/provider/group_test.go
index 88d110ae..98f53514 100644
--- a/internal/provider/group_test.go
+++ b/internal/provider/group_test.go
@@ -25,7 +25,7 @@ func TestAutoGroupsSameModel(t *testing.T) {
 		e("openrouter", "anthropic/claude-opus-5.5", "anthropic/claude-opus-5.5"),
 		e("copilot", "claude-opus-5.5", "claude-opus-5.5"),
 		e("claude", "claude-opus-5-5", "Claude Opus 5.5"),
-	})
+	}, nil)
 	if len(gs) != 1 || gs[0].ID != "auto-claude-opus-5-5" || len(gs[0].Members) != 3 || gs[0].Name != "Claude Opus 5.5" {
 		t.Fatalf("groups: %+v", gs)
 	}
diff --git a/internal/provider/modelprefs.go b/internal/provider/modelprefs.go
index 53e99137..eacc56c4 100644
--- a/internal/provider/modelprefs.go
+++ b/internal/provider/modelprefs.go
@@ -426,18 +426,21 @@ func (p Provider) ModelAPI(model string) (Protocol, bool) {
 // ModelPref is what the provider editor's Names & levels changed of one
 // model, sent with its Save: each part left nil is as it was. Name "" gives
 // the model its own name back, Efforts [] all its levels, OwnImages the
-// vendor's answer for whether it sees images, and API "" every API the
-// provider has for it.
+// vendor's answer for whether it sees images, API "" every API the
+// provider has for it, and Same "" its own id to merge it with other
+// vendors' by (see SetModelSame).
 type ModelPref struct {
 	Name      *string   `json:"name,omitempty"`
 	Efforts   *[]string `json:"efforts,omitempty"`
 	Images    *bool     `json:"images,omitempty"`
 	OwnImages bool      `json:"ownImages,omitempty"`
 	API       *string   `json:"api,omitempty"`
+	Same      *string   `json:"same,omitempty"`
 }
 
 // SetModelPrefs makes the changes to a provider's models, by model id, as
-// SetModelName, SetModelEfforts, SetModelImage and SetModelAPI do, and tells the agents
+// SetModelName, SetModelEfforts, SetModelImage, SetModelAPI and
+// SetModelSame do, and tells the agents
 // once, after them all, rather than once a change. It stops at the first
 // that fails, telling the agents of those made before it.
 func SetModelPrefs(pid string, prefs map[string]ModelPref) error {
@@ -473,12 +476,66 @@ func SetModelPrefs(pid string, prefs map[string]ModelPref) error {
 					return err
 				}
 			}
+			if m.Same != nil {
+				if err := set(setModelSame(ref, *m.Same)); err != nil {
+					return err
+				}
+			}
 		}
 		return nil
 	}()
 	return touchedIf(changed, err)
 }
 
+// SetModelSame says which model a provider's model, spelt "provider/model",
+// is the same as, for one a vendor names its own way (Volcengine Ark's
+// dated ids, kyzhouxu on #583): the routing groups magpie finds merge it
+// with that model from every other provider (autoGroups). The name is a
+// model's id as any vendor spells it ("deepseek-v4.1-flash", or with a
+// vendor's prefix); "" — or a name that is the model's own however spelt —
+// merges it by its own id again. The agents are told, the groups they are
+// shown having changed.
+func SetModelSame(ref, same string) error {
+	return touchedIf(setModelSame(ref, same))
+}
+
+func setModelSame(ref, same string) (bool, error) {
+	p, model, err := splitRef(ref)
+	if err != nil {
+		return false, err
+	}
+	same = strings.TrimSpace(same)
+	if len([]rune(same)) > 80 {
+		return false, errors.New("the model a model is the same as is at most 80 characters")
+	}
+	if same != "" && Slug(sameModel(same)) == "" {
+		return false, fmt.Errorf("%q names no model: give a model's id, as deepseek-v4.1-flash", same)
+	}
+	if sameModel(same) == sameModel(model) {
+		same = "" // its own id: merged by it already
+	}
+	if same != "" && !p.serves(model) {
+		return false, fmt.Errorf("%s has no model %s (magpie provider %s lists them)", p.ID, model, p.ID)
+	}
+	s := settings.Load()
+	key := p.ID + "/" + model
+	if s.ModelSameAs[key] == same {
+		return false, nil
+	}
+	if same == "" {
+		delete(s.ModelSameAs, key)
+	} else {
+		if s.ModelSameAs == nil {
+			s.ModelSameAs = map[string]string{}
+		}
+		s.ModelSameAs[key] = same
+	}
+	if err := settings.Save(s); err != nil {
+		return false, err
+	}
+	return true, nil
+}
+
 // ImageOverride is the user's answer for whether pid's model takes images.
 func ImageOverride(pid, model string) (bool, bool) {
 	v, ok := settings.Load().ModelImages[pid+"/"+model]
diff --git a/internal/provider/modelsame_test.go b/internal/provider/modelsame_test.go
new file mode 100644
index 00000000..2710ec30
--- /dev/null
+++ b/internal/provider/modelsame_test.go
@@ -0,0 +1,131 @@
+package provider
+
+import (
+	"slices"
+	"strings"
+	"testing"
+
+	"github.com/yetone/magpie/internal/catalog"
+	"github.com/yetone/magpie/internal/settings"
+)
+
+// The groups magpie finds merge a model however a vendor spells its id:
+// Volcengine Ark's dated deepseek-v4-1-flash-260910 is ali's
+// deepseek-v4.1-flash (kyzhouxu, #583). Models that differ stay apart.
+func TestSameModelVendorSpellings(t *testing.T) {
+	for in, want := range map[string]string{
+		// Ark's YYMMDD snapshot
+		"deepseek-v4-1-flash-260910":      "deepseek-v4-1-flash",
+		"deepseek-v4.1-flash":             "deepseek-v4-1-flash",
+		"DeepSeek-V4.1-Flash":             "deepseek-v4-1-flash",
+		"deepseek-ai/DeepSeek-V4.1-Flash": "deepseek-v4-1-flash",
+		"doubao-seed-1-6-250615":          "doubao-seed-1-6",
+		"doubao-seed-1.6-thinking-250715": "doubao-seed-1-6-thinking",
+		// Fireworks: its path, and "p" for the dot
+		"accounts/fireworks/models/deepseek-v4p1-flash": "deepseek-v4-1-flash",
+		"accounts/fireworks/models/qwen2p5-72b":         "qwen2-5-72b",
+		// "_" for "-", and Vertex's "@" date
+		"deepseek_v4_1_flash":      "deepseek-v4-1-flash",
+		"claude-opus-5-5@20260801": "claude-opus-5-5",
+		// not a date: kept
+		"deepseek-v4-1-flash-128000": "deepseek-v4-1-flash-128000",
+		"m-221301":                   "m-221301",
+		"m-261301":                   "m-261301",
+		"m-260100":                   "m-260100",
+		"qwen3-235b-a22b-2507":       "qwen3-235b-a22b-2507",
+		"kimi-k2-0905":               "kimi-k2-0905",
+		"gpt-4o":                     "gpt-4o",
+		"o3-pro":                     "o3-pro",
+		"llama-3p":                   "llama-3p",
+	} {
+		if got := sameModel(in); got != want {
+			t.Errorf("sameModel(%q) = %q, want %q", in, got, want)
+		}
+	}
+	// genuinely different models: never one group
+	for _, pair := range [][2]string{
+		{"deepseek-v4-1-flash-260910", "deepseek-v4.1"},
+		{"deepseek-v4-1-260910", "deepseek-v4.1-flash"},
+		{"deepseek-v4.1-thinking", "deepseek-v4.1"},
+		{"qwen3-235b-a22b-2507", "qwen3-235b-a22b"},
+		{"claude-opus-5.5:batch", "claude-opus-5.5"},
+		{"deepseek-v4.1-flash", "deepseek-v4.11-flash"},
+	} {
+		if sameModel(pair[0]) == sameModel(pair[1]) {
+			t.Errorf("%s and %s merged as %s", pair[0], pair[1], sameModel(pair[0]))
+		}
+	}
+	e := func(p, m string) Entry { return Entry{ID: p + "/" + m, Model: m, Name: m, Provider: Provider{ID: p}} }
+	gs := autoGroups([]Entry{e("volcengine", "deepseek-v4-1-flash-260910"), e("ali-tp", "deepseek-v4.1-flash")}, nil)
+	if len(gs) != 1 || gs[0].ID != "auto-deepseek-v4-1-flash" || !slices.Equal(gs[0].Members, []string{"volcengine/deepseek-v4-1-flash-260910", "ali-tp/deepseek-v4.1-flash"}) {
+		t.Fatalf("groups: %+v", gs)
+	}
+}
+
+// A model whose id no rule matches up with another vendor's is merged
+// with it once the user says, in the provider's Names & levels, which
+// model it is the same as (#583): saved with the provider's Save, kept in
+// settings' ModelSameAs, and taken by the groups magpie finds.
+func TestModelSameAsMergesFoundGroup(t *testing.T) {
+	prefsHome(t)
+	touched := 0
+	catalog.Changed = func() { touched++ }
+	t.Cleanup(func() { catalog.Changed = nil })
+	if err := Save(Provider{ID: "c", Name: "C", Key: "k", Chat: "http://127.0.0.1:1/v1", Models: []string{"ep-sol-x"}}); err != nil {
+		t.Fatal(err)
+	}
+	members := func(gid string) []string {
+		_, ms, ok := FindGroup(GroupPrefix + gid)
+		if !ok {
+			return nil
+		}
+		var out []string
+		for _, m := range ms {
+			out = append(out, m.ID)
+		}
+		return out
+	}
+	if got := members("auto-sol"); !slices.Equal(got, []string{"a/sol", "b/sol"}) {
+		t.Fatalf("before: %v", got)
+	}
+	touched = 0
+	same := "Vendor/SOL"
+	if err := SetModelPrefs("c", map[string]ModelPref{"ep-sol-x": {Same: &same}}); err != nil {
+		t.Fatal(err)
+	}
+	if touched != 1 || settings.Load().ModelSameAs["c/ep-sol-x"] != "Vendor/SOL" {
+		t.Fatalf("told %d, saved %v", touched, settings.Load().ModelSameAs)
+	}
+	if got := members("auto-sol"); !slices.Equal(got, []string{"a/sol", "b/sol", "c/ep-sol-x"}) {
+		t.Fatalf("after: %v", got)
+	}
+	if AutoGroupOf("c", "ep-sol-x") != "auto-sol" || AutoGroupID("ep-sol-x") != "auto-ep-sol-x" {
+		t.Fatalf("AutoGroupOf %s", AutoGroupOf("c", "ep-sol-x"))
+	}
+	if g, ok := GroupFor("sol"); !ok || g != GroupPrefix+"auto-sol" {
+		t.Fatalf("GroupFor: %s %v", g, ok)
+	}
+	// the same again: nothing to tell
+	if err := SetModelPrefs("c", map[string]ModelPref{"ep-sol-x": {Same: &same}}); err != nil || touched != 1 {
+		t.Fatalf("%v, told %d", err, touched)
+	}
+	// its own id however spelt is no mapping: nothing kept
+	own := "c/EP_Sol-X"
+	if err := SetModelPrefs("c", map[string]ModelPref{"ep-sol-x": {Same: &own}}); err != nil {
+		t.Fatal(err)
+	}
+	if _, ok := settings.Load().ModelSameAs["c/ep-sol-x"]; ok || touched != 2 {
+		t.Fatalf("kept %v, told %d", settings.Load().ModelSameAs, touched)
+	}
+	if got := members("auto-sol"); !slices.Equal(got, []string{"a/sol", "b/sol"}) {
+		t.Fatalf("restored: %v", got)
+	}
+	// a model the provider doesn't serve, or a name of no model, is refused
+	if err := SetModelPrefs("c", map[string]ModelPref{"nope": {Same: &same}}); err == nil || !strings.Contains(err.Error(), "nope") {
+		t.Fatalf("got %v", err)
+	}
+	junk := "--/"
+	if err := SetModelPrefs("c", map[string]ModelPref{"ep-sol-x": {Same: &junk}}); err == nil {
+		t.Fatal("a name of no model was taken")
+	}
+}
diff --git a/internal/provider/provider_order_test.go b/internal/provider/provider_order_test.go
index e248b0c7..fafb383a 100644
--- a/internal/provider/provider_order_test.go
+++ b/internal/provider/provider_order_test.go
@@ -38,11 +38,11 @@ func TestProviderOrder(t *testing.T) {
 	if p, _, ok := Resolve("m"); !ok || p.ID != "c" {
 		t.Fatalf("m resolves to %q, not c", p.ID)
 	}
-	g := slices.IndexFunc(autoGroups(providerEntries()), func(g Group) bool { return g.ID == AutoGroupID("m") })
+	g := slices.IndexFunc(autoGroups(providerEntries(), nil), func(g Group) bool { return g.ID == AutoGroupID("m") })
 	if g < 0 {
 		t.Fatal("no group found of m")
 	}
-	if ms := autoGroups(providerEntries())[g].Members; !slices.Equal(ms, []string{"c/m", "a/m", "b/m"}) {
+	if ms := autoGroups(providerEntries(), nil)[g].Members; !slices.Equal(ms, []string{"c/m", "a/m", "b/m"}) {
 		t.Fatalf("group of m tries %v", ms)
 	}
 	if err := Save(Provider{ID: "d", Name: "d", Key: "sk-d", Chat: "https://d.example.com/v1", Models: []string{"m"}}); err != nil {
diff --git a/internal/settings/settings.go b/internal/settings/settings.go
index 8c29d35d..c69cd016 100644
--- a/internal/settings/settings.go
+++ b/internal/settings/settings.go
@@ -251,6 +251,12 @@ type Settings struct {
 	// (01huadalang on Discord). Absent leaves it to the vendor's list and
 	// to each URL the provider has (see provider.SetModelAPI).
 	ModelAPIs map[string]string `json:"modelAPIs,omitempty"`
+	// ModelSameAs is the model another vendor sells under another name
+	// that a model is, by "<provider id>/<model id>": the routing groups
+	// magpie finds (provider's autoGroups) merge it with that one rather
+	// than by its own id, for an id no rule of magpie's matches up
+	// (kyzhouxu, #583). Absent leaves it to its id.
+	ModelSameAs map[string]string `json:"modelSameAs,omitempty"`
 	// The main window's size when it was last resized, width and height,
 	// so it opens at it again after a restart.
 	Window []int `json:"window,omitempty"`