[Basssiiie]

If I were you I would go for a wider solution: run multiple "games" at once. Only one game is open for public at all time. For example; players join like with option 1. When there are enough players and the round starts, the current game is locked off for new players and a new "game/lobby" is created for the players who join next. So in the end you'll have like 5 "games/lobbies" running simultaneously on the same server. In the end, when a game finishes, you just dump everyone into the current open game lobby.

In short:

• There is always one game lobby open, at every possible time.
• In the background, there are multiple games running filled with players.

It would require a strong server than option 1, but this doesn't scare people away when a game is already running.

Edit: you could split the games up with virtual worlds and limit chat only to the game the player is in.