Initially I was offered a choice between multi-player and single player modes - so having both is not uncommon or infeasible. Then when I got to the multi-player set up, it told me how many people were currently playing in how many games, and how many games were waiting to kick off. In a 'lobby' effectively. The other thing it allowed was the option to create or join a password protected game.
Those options appear to cover the following options rather well:
- You want to play alone.
- You want to play against someone else, but you don't care who.
- A minimum number is required for a game.
- If a game is still in the right stage and below the maximum you could join an existing game.
- You want to play against your friends and only your friends.
Sweet! Answers a few things I'd been struggling with how to design in!