If you tried to host a room with the same name, then yes it will join the first room with he same name.
Perhaps post a capx.
Capx doesn't matter, even if I try it with the built-in "Multiplayer game" example, it's still not working. My project is based on that, structured very similarly, esp. the signalling part.
What I was thinking, was a special alias for the host, and room name would be the host name. If the host alias doesn't start with that value ---> kick peer, that's not me. The string value wouldn't be stored in a C2 variable, because it could be seen in the exported Javascript. I would get it from a database, plus keep track of the rooms.
I just though maybe there's a simpler solution?