Honestly, tanking in H VH is about making sure everyone knows their priorities. You can't really mark them because of time, but just set out a pre-emptive kill order. I do the mage type first, because they frequently drop aggro anyway to do that channelled spell, are annoying with the knockback spell, and if a DPS does steal aggro, they're just gonna eat mostly magic damage. The rogue types, stalker I think, should go down next simply becase of their annoying teleport ability. Third type, can't remember name, hunters maybe? And lastly, the captains. Everytime I've seen tank trouble or had it myself it's because some moron decides to solo the captain and then get's a spear or seven in the face. It's to the point where I always ask if people know the bosses and I always set up the kill order before hand. Really though, this in general should be common knowledge for most DPS for unmarkable mobs (caster/ranged/AOEers take priority over basic warrior types). Or are you having just general problems with AOEers?