The simple variant i used is multiplayer.Launch first game choose you profile in main menu.Select new multiplayer game and create.
2.Launch another instance of DOS.Create a new profile choose multiplayer game-connect
3.Repeat step 2 2 more times.each time creating a new profile
4.IF you Pc not so strong recommend to do this in window mode with minimum resolution.
5.start multiplayer game-create party.start game.save game.quit another instances of game.Profit.