diff --git a/admin_menu.api.php b/admin_menu.api.php
index 2d212fb..f3765d9 100644
--- a/admin_menu.api.php
+++ b/admin_menu.api.php
@@ -162,3 +162,43 @@ function hook_admin_menu_cache_info() {
   );
   return $caches;
 }
+
+/**
+ * Alter the Cache ID used to cache a rendered admin_menu.
+ *
+ * By default the admin menu is cached by:
+ * - The User ID.
+ * - The session ID.
+ * - The current language.
+ *
+ * Some implementations will add extra items to the menu (or alter it) based on
+ * the context of the page (e.g. Extra menu items when in an Organic Group).
+ * As the admin menu is by default generated and cached once, the context
+ * specific items will be missing/out of place unless the cache is cleared.
+ *
+ * This hook allows to alter the Cache ID based on a context.
+ *
+ * A cache id is by default:
+ * <code>
+ * admin_menu:uid:session_id:language
+ * </code>
+ *
+ * Where:
+ * - admin_menu : Fixed cache id prefix.
+ * - uid : The current User ID.
+ * - session_id : The PHP session ID.
+ * - language : The current language code (eg. en, fr, ...).
+ *
+ * WARNING: The cid will always start with "admin_menu:uid:".
+ *          This because of the functionality to clear the admin_menu cache.
+ *
+ * @param string $cid
+ *   The Cache ID to be altered.
+ */
+function hook_admin_menu_cache_id_alter(&$cid) {
+  // Add the Group ID to the Cache ID.
+  $context = og_context('node');
+  if ($context) {
+    $cid .= ':' . $context['gid'];
+  }
+}
diff --git a/admin_menu.module b/admin_menu.module
index 21bff9f..0eafc10 100644
--- a/admin_menu.module
+++ b/admin_menu.module
@@ -154,7 +154,7 @@ function admin_menu_page_build(&$page) {
   if (strpos($_GET['q'], 'js/') === 0) {
     return;
   }
-  global $user, $language;
+  global $user;
   $path = drupal_get_path('module', 'admin_menu');
 
   $page['page_bottom']['admin_menu'] = array(
@@ -184,7 +184,8 @@ function admin_menu_page_build(&$page) {
 
   // If the client supports JavaScript and we have a cached menu for the current
   // user, only output the hash for the client-side HTTP cache callback URL.
-  $cid = 'admin_menu:' . $user->uid . ':' . session_id() . ':' . $language->language;
+  $cid = admin_menu_cache_id();
+
   if (!$complete && !empty($_COOKIE['has_js']) && ($hash = admin_menu_cache_get($cid))) {
     $settings['hash'] = $hash;
     // The base path to use for cache requests depends on whether clean URLs
@@ -276,6 +277,38 @@ function admin_menu_js() {
 }
 
 /**
+ * Get the Cache ID to store rendered admin menu in cache.
+ *
+ * Some implementations will add extra items to the menu (or alter it) based on
+ * the context the page is in (e.g. Extra menu items when in an Organic Group).
+ *
+ * The admin_menu is by default cached by:
+ * - The User ID.
+ * - The session ID.
+ * - The current language.
+ *
+ * So once a menu is cached for one context, it will shown like even if there is
+ * another context. Unless the cache is cleared.
+ *
+ * This function will create a default cache ID but this one can be altered by
+ * implementing hook_admin_menu_cache_id_alter().
+ *
+ * WARNING: The cid must always start with "admin_menu:UID".
+ *          This because of the functionality to clear the admin_menu cache.
+ *
+ * @return string
+ *   The Cache ID.
+ */
+function admin_menu_cache_id() {
+  global $user, $language;
+
+  $cid = 'admin_menu:' . $user->uid . ':' . session_id() . ':' . $language->language;
+  drupal_alter('admin_menu_cache_id', $cid);
+
+  return $cid;
+}
+
+/**
  * Retrieve a client-side cache hash from cache.
  *
  * The hash cache is consulted more than once per request; we therefore cache
@@ -451,10 +484,8 @@ function admin_menu_session_count($timestamp = 0, $anonymous = TRUE) {
  *   page.
  */
 function admin_menu_output($complete = FALSE) {
-  global $user, $language;
-
   $cache_server_enabled = !$complete && variable_get('admin_menu_cache_server', TRUE);
-  $cid = 'admin_menu:' . $user->uid . ':' . session_id() . ':' . $language->language;
+  $cid = admin_menu_cache_id();
 
   // Try to load and output administration menu from server-side cache.
   // @todo Duplicates the page cache? Page cache ID contains the hash that is