When you redirect, are you redirecting to an activity that honors the original impulse?
In Becoming the Parent YOu Want To Be, they make a distinction between redirection and distraction- redirection is related to the activity at hand. That way they can continue expressing that impulse, but in an acceptable way. Distraction can be anything, just to get their attention away from what they were doing.
For your kids, I'd say to make sure you redirect to something related. If they are fighting because they are angry, tell them other ways to express their anger- roar like a lion, make a mad face, clap their hands hard, whatever. Also, let them know how to express what the problem is- if someone won't move out of the other's way, remind him how to say "MOVE!" in words or sign language.
That was a big one for my ds, with the dogs. I told him to make a stop sign with his hand, and yell for me to help. It made a huge difference.
If its just playing that got out of hand, I'd say to redirect to something physical. Do you have pounding toys? (but I'd be careful- I'd not want to redirect an angry child to hit something else). Or balls?
I've never had the situation you have, but my solution to everything is to redirect in a way that honors the original impulse. lol.