diff --git a/example-config.yaml b/example-config.yaml
index c97bd70c..5c312147 100644
--- a/example-config.yaml
+++ b/example-config.yaml
@@ -292,6 +292,13 @@ bridge:
             # When private_chat_invite is empty, this message is sent to users /starting the
             # relaybot. Telegram's "markdown" is supported.
             message: This is a Matrix bridge relaybot and does not support direct chats
+        # List of users to invite to all group chat portals created by the bridge.
+        group_chat_invite: []
+        # Whether or not the relaybot should not bridge events in unbridged group chats.
+        # If false, portals will be created when the relaybot receives messages, just like normal
+        # users. This behavior is usually not desirable, as it interferes with manually bridging
+        # the chat to another room.
+        ignore_unbridged_group_chat: true
         # Whether or not to allow creating portals from Telegram.
         authless_portals: true
         # Whether or not to allow Telegram group admins to use the bot commands.
diff --git a/mautrix_telegram/abstract_user.py b/mautrix_telegram/abstract_user.py
index 72fb69d1..0ad0dafd 100644
--- a/mautrix_telegram/abstract_user.py
+++ b/mautrix_telegram/abstract_user.py
@@ -351,6 +351,8 @@ class AbstractUser(ABC):
                                                                   Optional[po.Portal]]:
         if isinstance(update, UpdateShortChatMessage):
             portal = po.Portal.get_by_tgid(TelegramID(update.chat_id))
+            if not portal:
+                self.log.warning(f"Received message in chat with unknown type {update.chat_id}")
             sender = pu.Puppet.get(TelegramID(update.from_id))
         elif isinstance(update, UpdateShortMessage):
             portal = po.Portal.get_by_tgid(TelegramID(update.user_id), self.tgid, "user")
@@ -404,7 +406,9 @@ class AbstractUser(ABC):
 
     async def update_message(self, original_update: UpdateMessage) -> None:
         update, sender, portal = self.get_message_details(original_update)
-        if portal and not portal.allow_bridging:
+        if not portal:
+            return
+        elif portal and not portal.allow_bridging:
             self.log.debug(f"Ignoring message in portal {portal.tgid_log} (bridging disallowed)")
             return
 
@@ -413,10 +417,9 @@ class AbstractUser(ABC):
                 if not config["bridge.relaybot.private_chat.invite"]:
                     self.log.debug(f"Ignoring private message to bot from {sender.id}")
                     return
-            elif not portal or not portal.mxid:
-                tgid_log = portal.tgid_log if portal else original_update.chat_id
-                self.log.debug(
-                    f"Ignoring message received by bot in unbridged chat {tgid_log}")
+            elif not portal.mxid and config["bridge.relaybot.ignore_unbridged_group_chat"]:
+                self.log.debug("Ignoring message received by bot"
+                               f" in unbridged chat {portal.tgid_log}")
                 return
 
         if self.ignore_incoming_bot_events and self.relaybot and sender.id == self.relaybot.tgid:
diff --git a/mautrix_telegram/config.py b/mautrix_telegram/config.py
index f13cb442..37c7be4a 100644
--- a/mautrix_telegram/config.py
+++ b/mautrix_telegram/config.py
@@ -154,6 +154,8 @@ class Config(BaseBridgeConfig):
             copy("bridge.relaybot.private_chat.invite")
             copy("bridge.relaybot.private_chat.state_changes")
             copy("bridge.relaybot.private_chat.message")
+            copy("bridge.relaybot.group_chat_invite")
+            copy("bridge.relaybot.ignore_unbridged_group_chat")
             copy("bridge.relaybot.authless_portals")
             copy("bridge.relaybot.whitelist_group_admins")
             copy("bridge.relaybot.whitelist")
diff --git a/mautrix_telegram/portal/metadata.py b/mautrix_telegram/portal/metadata.py
index 03efa681..31f2049d 100644
--- a/mautrix_telegram/portal/metadata.py
+++ b/mautrix_telegram/portal/metadata.py
@@ -293,11 +293,15 @@ class PortalMetadata(BasePortal, ABC):
         users = participants = None
         if not direct:
             users, participants = await self._get_users(user, entity)
+            extra_invites = config["bridge.relaybot.group_chat_invite"]
+            invites += extra_invites
+            for invite in extra_invites:
+                power_levels.users.setdefault(invite, 100)
             self._participants_to_power_levels(participants, power_levels)
         elif self.bot and self.tg_receiver == self.bot.tgid:
             invites = config["bridge.relaybot.private_chat.invite"]
             for invite in invites:
-                power_levels.users[invite] = 100
+                power_levels.users.setdefault(invite, 100)
             self.title = puppet.displayname
         initial_state = [{
             "type": EventType.ROOM_POWER_LEVELS.serialize(),