Severing body parts

Hi,

If I get all the collision bounding box code implemented so that I can detect which part of a model is being hit, how can I make it such that if you hit an arm, the arm is chopped off (with appropriate blood sprayage)? Is there a way to say "Now for this particular entity, hide groups LeftUpperArm, LeftLowerArm, LeftHand" (going by the group names I use for my model in Milkshape)? What's the best way to make this happen? I basically want my players/bots to be able to dismember each other piece by piece, without dying until the head is removed.

Also, for the blood, how would I get the effect of a splatter on the model in the area of the collision, such that the blood stains the skin/clothing and stays there until that char is dead and gone? And how about for a constant spray of blood from say a shoulder socket? Would that one be a particleemitter? Can I keep it turned on, on the model, possibly from various spots, without bogging down the game?

Glez