diff --git a/lib/selectors/thread-selectors.js b/lib/selectors/thread-selectors.js
--- a/lib/selectors/thread-selectors.js
+++ b/lib/selectors/thread-selectors.js
@@ -200,6 +200,27 @@
   },
 );
 
+const containedThreadInfos: (state: BaseAppState<*>) => {
+  +[id: string]: $ReadOnlyArray<ThreadInfo>,
+} = createSelector(
+  threadInfoSelector,
+  (threadInfos: { +[id: string]: ThreadInfo }) => {
+    const result = {};
+    for (const id in threadInfos) {
+      const threadInfo = threadInfos[id];
+      const containingThreadID = threadInfo.containingThreadID;
+      if (containingThreadID === null || containingThreadID === undefined) {
+        continue;
+      }
+      if (result[containingThreadID] === undefined) {
+        result[containingThreadID] = [];
+      }
+      result[containingThreadID].push(threadInfo);
+    }
+    return result;
+  },
+);
+
 function getMostRecentRawMessageInfo(
   threadInfo: ThreadInfo,
   messageStore: MessageStore,
@@ -453,6 +474,7 @@
   entryInfoSelector,
   currentDaysToEntries,
   childThreadInfos,
+  containedThreadInfos,
   unreadCount,
   unreadBackgroundCount,
   otherUsersButNoOtherAdmins,