Full RoH combo on tail when it appears.
Get to the adds, shield lob one, CoS the other, fash on both, continue flash spam. (Provoke an add back if needed). After enough flashes go back to tail before adds are dead (the dps will finish them off for you anyway), combo away on tail.

Single add spawns, you just grab it with whatever, or run to the person that has aggro (you going to stun lock this one anyway so having threat on it doesn't really matter anyway)