To play with four players on the same team, do the following: Player 2 must be using a wireless controller. Turn three controllers on and select the same team with the first two controllers. When the game starts, press Start with controller 1. Turn off controller 2. Set all three controllers to the same team. Turn back on controller 2 just before resuming the game.
To get four human players on the same team, do the above and press start on controller 3. Turn controllers 1 and 2 off. With controller 3 go to the controller setup and move player 4 to the same team as player 3. Turn controllers 1 and 2 back on just before resuming the game.