Pausing Game

When my map starts, Player 1 gets to choose what type of game the map will play, but the game continues while he has this Dialog Menu up... Is there any better way to pause the game than to use the trigger "Unpause/Pause Game".
It's very annoying since people can unpause the game before Player 1 is done.

Pause all units and don't start the triggers until player 1 finishes?

You can pause all units, then no one can do something.

Edit: Damn, Griffen was faster -.-

Why start a game before you know what type it is? Just don't show any part of the map, so everyone's looking at a black screen until the type is chosen.