diff --git a/src/team_bot/bot.py b/src/team_bot/bot.py
index 351fd87..4c79d5e 100644
--- a/src/team_bot/bot.py
+++ b/src/team_bot/bot.py
@@ -234,21 +234,10 @@ class RelayPlugin:
 
     def is_relay_group(self, chat: deltachat.Chat) -> bool:
         """Check whether a chat is a relay group."""
-        if not chat.get_name().startswith(
-            "[%s] " % (self.account.get_config("addr").split("@")[0],)
-        ):
-            return False  # all relay groups' names begin with a [tag] with the localpart of the team-bot's address
-        if (
-            chat.get_messages()[0].get_sender_contact()
-            != self.account.get_self_contact()
-        ):
-            return False  # all relay groups were started by the team-bot
-        if chat.is_protected():
-            return False  # relay groups don't need to be protected, so they are not
-        for crew_member in self.crew.get_contacts():
-            if crew_member not in chat.get_contacts():
-                return False  # all crew members have to be in any relay group
-        return True
+        for mapping in self.kvstore.get("relays"):
+            if mapping[1] == chat.id:
+                return True
+        return False
 
     def get_outside_chat(self, relay_group_id: int) -> deltachat.Chat:
         """Get the corresponding outside chat for the ID of a relay group.
diff --git a/tests/test_bot.py b/tests/test_bot.py
index 27a684d..7f8621a 100644
--- a/tests/test_bot.py
+++ b/tests/test_bot.py
@@ -27,6 +27,12 @@ def test_not_relay_groups(relaycrew, outsider, lp):
     bot = relaycrew.bot
     user = relaycrew.user
 
+    def find_msg(ac, text):
+        for chat in ac.get_chats():
+            for msg in chat.get_messages():
+                if msg.text == text:
+                    return msg
+
     text = "outsider -> bot 1:1 chat"
     lp.sec(text)
     outsider_botcontact = outsider.create_contact(bot.get_config("addr"))
@@ -38,6 +44,14 @@ def test_not_relay_groups(relaycrew, outsider, lp):
     assert bot_message_from_outsider.text == text
     assert not bot.relayplugin.is_relay_group(bot_outside_chat)
 
+    lp.sec("leave relay group with user")
+    relayed_msg = find_msg(user, text)
+    if not relayed_msg:
+        relayed_msg = user._evtracker.wait_next_incoming_message()
+    relayed_msg.chat.remove_contact(user.get_config("addr"))
+    leave_msg = bot._evtracker.wait_next_incoming_message()
+    assert bot.relayplugin.is_relay_group(leave_msg.chat)
+
     text = "outsider -> bot group chat"
     lp.sec(text)
     outsider_bot_group = outsider.create_group_chat(
@@ -58,12 +72,6 @@ def test_not_relay_groups(relaycrew, outsider, lp):
 
     # somehow the message doesn't trigger DC_EVENT_INCOMING_MSG
     # bot._evtracker.wait_next_incoming_message()
-    def find_msg(ac, text):
-        for chat in ac.get_chats():
-            for msg in chat.get_messages():
-                if msg.text == text:
-                    return msg
-
     bot_message_from_user = find_msg(bot, text)
     while not bot_message_from_user:
         bot_message_from_user = find_msg(bot, text)