The Simpsons Arcade Game

To perform a Team Attack, stand still to another player, neither of you moving. Lisa and Bart will hold hands and run forward damaging everyone, Marge with Lisa or Bart, will pick them up then throw them, Marge with Homer will hold hands and begin rolling around damaging everyone, Homer with Lisa or Bart, will put them on his shoulders for them to attack. Fortunately, this doesn't need to be all at once since it's cumulative.

Alternatively, Go to the character select screen, hold down the button and switch between all 4 ports. You can select all 4 characters with one controller this way without the game stopping you. Start the game with Bart and have the other 'player' be Lisa, go stand next to her and you will hold hands. Now just run around damaging all the enemies and you should get it in no time!