Right, I think I addressed this before: I would like to see a hockey-like rule adopted (or adapted to baseball) where if anyone. besides the two principals to a fight, participates in the fight, then they are to be severely penalized.
That would go a long way to putting an end to this because the overwhelming majority of players don't truly want to engage. They should also add a rule that if you charge the mound and don't fight you get suspended for 30 games.