I did this with my Demon Hunter alt but im sure this can be done with another kitting class like Wizard im not sure about witch doctor, don't get me started about the barbarian.
You dont need amazing DPS to take these elite packs down just need to be able to kite them with the help of Tyrael it makes it so much easier.
Here Is The Build I Use For Demon Hunter:-
Demon Hunter - Game Guide - Diablo III
1) You Need To Get Lucky Getting The Kiting Area On The Map! From My Experience It Spawns Often
2) Find Yourself A Blue Pack ( Leave The Boss For Now ) They Are Pretty Close
3) Kite Kill Them Around The Area ( If You Get Enrage Timer Just Reset You Should Have 1-2 Down By Then Away Depending On Your DPS)
4) Go Kill Boss
5)Repeat
Notice That I Had No Nephalem Valor Buff Then Had 2! Its Bugged So When You Leave Game & Resume It Shows 0 Once You Kill An Elite Pack They All Come Back.
Repeat To Get 5 Stacks Loot Heaven.
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Regards
Nebe