Adding information to sessions and joining a session without sending players to the level

Hey there! I’m new to Unreal Engine, and have been working on a game. It’s multiplayer, and I am of course using sessions to allow players to join each other’s games. The game has multiple different game modes, and I want players to search for games based on a game mode. However, I have found no way to add any extra info so that I can determine what game mode a server has. How can I do this?

Besides that, players also need to wait until their game has enough players to start. How can I make it so that players join a session (so that the session knows it has enough players) without already sending them to the level, and keeping them in my main menu?