Simultaneous turns?

I’m actually working on a module with this feature. The cardboard version of the game has simultaneous pre-planned moves, a lot like Diplomacy but more detailed.

In the Vassal version, each player’s pieces will have the Invisible trait. They will hide their pieces with a Global Key Command, move them invisibly, and then reveal their pieces again (probably with the same GKC). It’s a lot quicker than plotting out moves.