I know that this would probably require a complete server overhaul, and users can already use discord or other third-party programs to contact another player.

However, I have personally experienced the issue of trying to contact somebody in a full lobby
through a third-party program, but they don't respond/don't notice I've messaged them.
This could be a good implementation in TBN though, since it's still in development, and I believe servers have not yet been established in TBN

Now, as I said, this would be a tedious implementation for TB and easier for TBN, but it's just a suggestion after all, right?

Either way, since TBN servers haven't been established yet (to my understanding), it would be easier for group chats like that to be implemented in TBN rather than TB