I have similar setup at Vet 15 and I struggle doing this on my own. Infact I dont even get past first couple of ads
Try locking a few of them down to less the preasure on you, using agony on one(dont atack him for 30 seconds and you'll be fine) and mass hysteria on 3 others and then chose targets to single target. I recomend using agony instead of voley on bow bar and mass hysteria instead of relentless focus on 2h bar. That way you wil get tons of stuns out.