diff --git a/chat/indico_chat/controllers.py b/chat/indico_chat/controllers.py
index 221d535..750bf09 100644
--- a/chat/indico_chat/controllers.py
+++ b/chat/indico_chat/controllers.py
@@ -39,11 +39,9 @@ class RHChatEventPage(RHConferenceBaseDisplay):
 
     def _process(self):
         try:
-            event_id = int(self._conf.id)
+            chatrooms = ChatroomEventAssociation.find_for_event(self._conf).all()
         except ValueError:
             raise IndicoError('This page is not available for legacy events.')
-        chatrooms = ChatroomEventAssociation.find_all(ChatroomEventAssociation.event_id == event_id,
-                                                      ~ChatroomEventAssociation.hidden)
         cols = set()
         if any(c.chatroom.description for c in chatrooms):
             cols.add('description')
@@ -71,8 +69,7 @@ class RHChatManageEvent(RHChatManageEventBase):
     """Lists the chatrooms of an event"""
 
     def _process(self):
-        chatrooms = ChatroomEventAssociation.find_all(ChatroomEventAssociation.event_id == self.event_id,
-                                                      _eager='chatroom.events')
+        chatrooms = ChatroomEventAssociation.find_for_event(self.event, include_hidden=True, _eager='chatroom.events')
         chatroom_filter = (~Chatroom.id.in_(x.chatroom_id for x in chatrooms)) if chatrooms else True
         available_chatrooms = Chatroom.find_all(Chatroom.created_by_id == int(session.user.id), chatroom_filter)
         return WPChatEventMgmt.render_template('manage_event.html', self._conf, event_chatrooms=chatrooms,
diff --git a/chat/indico_chat/models/chatrooms.py b/chat/indico_chat/models/chatrooms.py
index c25f9f4..58c379c 100644
--- a/chat/indico_chat/models/chatrooms.py
+++ b/chat/indico_chat/models/chatrooms.py
@@ -172,3 +172,16 @@ class ChatroomEventAssociation(db.Model):
     @return_ascii
     def __repr__(self):
         return '<ChatroomEventAssociation({}, {})>'.format(self.event_id, self.chatroom)
+
+    @classmethod
+    def find_for_event(cls, event, include_hidden=False, **kwargs):
+        """Returns a Query that retrieves the chatrooms for an event
+
+        :param event: an indico event (with a numeric ID)
+        :param include_hidden: if hidden chatrooms should be included, too
+        :param kwargs: extra kwargs to pass to ``find()``
+        """
+        query = cls.find(event_id=int(event.id), **kwargs)
+        if not include_hidden:
+            query = query.filter(~cls.hidden)
+        return query
diff --git a/chat/indico_chat/plugin.py b/chat/indico_chat/plugin.py
index 1b3d8e0..861e600 100644
--- a/chat/indico_chat/plugin.py
+++ b/chat/indico_chat/plugin.py
@@ -98,8 +98,7 @@ class ChatPlugin(IndicoPlugin):
         self.register_js_bundle('chat_js', 'js/chat.js')
 
     def inject_event_header(self, event, **kwargs):
-        chatrooms = ChatroomEventAssociation.find_all(ChatroomEventAssociation.event_id == event.id,
-                                                      ~ChatroomEventAssociation.hidden)
+        chatrooms = ChatroomEventAssociation.find_for_event(event).all()
         if not chatrooms:
             return ''
         how_to_connect = self.settings.get('how_to_connect')
@@ -107,8 +106,7 @@ class ChatPlugin(IndicoPlugin):
                                       how_to_connect=how_to_connect, chat_links=self.settings.get('chat_links'))
 
     def _has_visible_chatrooms(self, event):
-        return bool(ChatroomEventAssociation.find(ChatroomEventAssociation.event_id == event.id,
-                                                  ~ChatroomEventAssociation.hidden).count())
+        return bool(ChatroomEventAssociation.find_for_event(event).count())
 
     def extend_event_menu(self, sender, **kwargs):
         return EventMenuEntry('chat.event_page', 'Chat Rooms', name='chat-event-page', plugin=True,