I'm not sure about the basketball direction, most of my confrontation training comes from soccer. The theory there is to "be the 3rd man in". If the officials are the 3rd person on the scene after the original two players then most of the other players won't try to retaliate. In this situation getting in the area and immediately sending the players to their benches would be best. Certainly one official should hang back and collect player numbers/monitor the benches but the other two officials should be in the middle right away.