diff --git a/ui/src/Stores/SilenceFormStore.js b/ui/src/Stores/SilenceFormStore.js
index 6e13963c7..8fb755850 100644
--- a/ui/src/Stores/SilenceFormStore.js
+++ b/ui/src/Stores/SilenceFormStore.js
@@ -51,18 +51,41 @@ const MatchersFromGroup = (group, stripLabels, alerts, onlyActive) => {
     }
   }
 
+  // this is the list of alerts we'll use to generate matchers
+  const filteredAlerts = (alerts ? alerts : group.alerts).filter(
+    (alert) => !onlyActive || alert.state === "active"
+  );
+
+  // array of arrays with label keys for each alert
+  const allLabelKeys = filteredAlerts
+    .map((alert) => Object.keys(alert.labels))
+    .filter((a) => a.length > 0);
+
+  // this is the list of label key that are shared across all alerts in the group
+  // https://stackoverflow.com/a/34498210/1154047
+  const sharedLabelKeys = allLabelKeys.length
+    ? allLabelKeys.reduce(function (r, a) {
+        var last = {};
+        return r.filter(function (b) {
+          var p = a.indexOf(b, last[b] || 0);
+          if (~p) {
+            last[b] = p + 1;
+            return true;
+          }
+          return false;
+        });
+      })
+    : [];
+
   // add matchers for all unique labels in this group
   let labels = {};
-  const allAlerts = alerts ? alerts : group.alerts;
-  for (const alert of allAlerts) {
-    if (!onlyActive || alert.state === "active") {
-      for (const [key, value] of Object.entries(alert.labels)) {
-        if (!stripLabels.includes(key)) {
-          if (!labels[key]) {
-            labels[key] = new Set();
-          }
-          labels[key].add(value);
+  for (const alert of filteredAlerts) {
+    for (const [key, value] of Object.entries(alert.labels)) {
+      if (sharedLabelKeys.includes(key) && !stripLabels.includes(key)) {
+        if (!labels[key]) {
+          labels[key] = new Set();
         }
+        labels[key].add(value);
       }
     }
   }
diff --git a/ui/src/Stores/SilenceFormStore.test.js b/ui/src/Stores/SilenceFormStore.test.js
index f3ea0f241..34555486a 100644
--- a/ui/src/Stores/SilenceFormStore.test.js
+++ b/ui/src/Stores/SilenceFormStore.test.js
@@ -211,6 +211,57 @@ describe("SilenceFormStore.data", () => {
     );
   });
 
+  it("fillMatchersFromGroup() handles alerts with different label sets", () => {
+    const group = MockAlertGroup(
+      { region: "AF" },
+      [
+        MockAlert([], {
+          alertname: "Alert1",
+          cluster: "prod",
+          foo: "bar",
+        }),
+        MockAlert([], {
+          alertname: "Alert2",
+          instance: "prod2",
+          cluster: "prod",
+        }),
+        MockAlert([], { alertname: "Alert3", instance: "dev1" }),
+      ],
+      [],
+      {
+        job: "mock",
+      },
+      {}
+    );
+    store.data.fillMatchersFromGroup(group, []);
+    expect(store.data.matchers).toHaveLength(3);
+    expect(store.data.matchers).toContainEqual(
+      expect.objectContaining({
+        name: "region",
+        values: [{ label: "AF", value: "AF" }],
+        isRegex: false,
+      })
+    );
+    expect(store.data.matchers).toContainEqual(
+      expect.objectContaining({
+        name: "alertname",
+        values: [
+          { label: "Alert1", value: "Alert1" },
+          { label: "Alert2", value: "Alert2" },
+          { label: "Alert3", value: "Alert3" },
+        ],
+        isRegex: true,
+      })
+    );
+    expect(store.data.matchers).toContainEqual(
+      expect.objectContaining({
+        name: "job",
+        values: [{ label: "mock", value: "mock" }],
+        isRegex: false,
+      })
+    );
+  });
+
   it("fillMatchersFromGroup() resets silenceID if set", () => {
     store.data.silenceID = "12345";
     const group = MockGroup();