Don,
If you can get the situation under control before it comes to blows, fine. Once the swinging starts it's time to backoff and start writing down numbers and let the coaches get the situation under control. An umpire should never get involved in a fight between players primarily for liability reasons. Frankly, this old bull is just getting to old to grapple with young teenage bucks, I rule by intimidation
BTW, FED makes the ejection list easy... anyone who isn't on the bench or near his assigned playing position and who isn't a coach who was trying to break up the brawl is gone,
--Sam