Do you mean an xbox live message, a Private message on this site or either or other form of message?
I'd like an invite but don't try to cram a 11 or more tournament players into a game lobby just to have them have connection issues and disconnect when the game starts.
Another words, have only the players on said table plus tourney manager at a table lobby.
Then have the tourney manager leave just before they start the game.
If the manager wants to play, he joins the last table he planned to coordinate.
Keep in mind the maximum amount of players per table is 10 & divide tables as evenly as possible.