6 Doctors?

I'd equate that to ripping my eye balls out with my fingernails.

I have a Doc at 175 and nothing makes my eyes bleed more then reading someone saying they are going to play 6 of them at a time. Feel free to do it but Doc's have one of the worst if not the worst attack rating in the game. Yes Doc's can tank some endgame bosses like LotV but it takes 30-60 minutes to do it solo. If you work your aggro right you can run 5 soldiers and 1 doc or even 5 NT's and 1 Doc but you need to be mindful of what you're trying to do.

If you plan to use NT's to sit their and AOE then your breed becomes the issue. I'd use Atrox for those NT's. Even though they have bad int the HP pool you have will help prevent them from dying from a random crit. Also roll your Agg/Def bar all the way to Def to get your def skills as high as possible.

If you're trying to mass kill with NT's it's best to do it with only 1 NT having them kite for the rest of the group.

5 NT's will work well with 1 doc if you stick to single targets and let the Doc pull with a non-breakable init debuff (UBT being the last and best of those) and watch the NT nukeage. Docs can keep aggro with just heals just avoid mashing the nuke button as fast as you can until you have CH.

Regarding CH'n for aggro, CH generates hate based off the amount healed so if you use it on a full HP teammate it will do little for you vs letting your doc get punched up a bit and CH'n then opening up on the mob.