How lo loot low level mobs with 2x8 Groups

[Sservis]

I'd try using non-damaging, but still offensive abilities, taunts, faerie fire, dispel magic, etc from one group with the other group going slightly slower with the one shot ability. As long as they cause threat, they should tag for that group, even if they're not doing any damage.

Edit to Add:
Also, for mobs over level 90, you probably can create a custom farming group fairly easily. Fresh DH start at 98 and likely don't 1 shot level 90s or even down into the high 80s, character boosts are 110. DK start at 55 if you want to do something in the 1 - 60+ range, etc