Hello Dario,
AppWarp Cloud maintain the room uniqueness based on room_id instead of room name to avoid the room creation calls rejection due to same room name. So, yes, if this is the requirement for your game you can get the all rooms and you can put a check on room name.
Another option is customising server side code, which is possible using AppWarpS2. With AppWarpS2, you can override the server side logic and can do the required customisation. It is an On-Premise solution which you can host on our GPaaS or any 3rd party hosting solutions.
Let me know if you have any further queries.
Thanks.