I'm lvling up my team right now. My main hunter is a 74 BM hunter sitting up resting till I get my new team up to match him. My team now is a Priest leading on main account and 3 BM hunters. All have bears and I don't pull aggro as long as I keep Aspect of the Viper up. First I send in the bears, then tag the mob with viper stings, then multishot. Right now, they're all lvl 33 and the only instance I've cleared with them is the Stockades at the same level. Grab some bears if you want a good tanking pet, they have Swipe and can get Thunderstomp now. With these two, you won't have many problems with them holding aggro as long as you don't go over board with your shooting spells. Aspect of the Viper may cut your damage in half, but you won't have to make so many breaks for mana and it helps keep your damage down from drawing aggro off your pet. Once you get volley, read up on how to use 'Click-on-Ground' AoE spells. Set a button of your choosing, then set your cursor on your slaves to about where your pets are. Toss up AoHawk, send in pets to pull mobs, run in and lay down your Explosive Traps for the AoE, then cast your Volley over your head for major damage. Go Discipline on your Priest to drop your threat from spells and cut the mana cost and increase healing. Mine hardly even heals as long as I keep Mend Pet up on my bears. Put Concussive Shot on a single button on all toons and put that button on Round Robin. Same goes for any other spell they have with a cooldown greater than 30seconds that puts the target to sleep or dazes them for x amount of seconds. Get talents that boost your pet's damage, armor, healing on them, and reduces any damage against them. I also never go above 50% on the AoE resistance on my pets cause there are not that many bad guys that cast AoE spells that won't last long enough to pop off 3 in a fight unless it's a boss or PvPer. But this is where Concussive Shot on round robin comes in handy. Once you down one mob, you'll have atleast one of you're toons CS spell ready for the next mob. Try this macro for your dps:

Hunter 1:
/assist focus
/castsequence reset=target: Viper Sting, Arcane Shot, Concussive Shot, Steady Shot, Steady Shot, Steady Shot

Hunter 2:
/assist focus
/castsequence reset=target: Viper Sting, Arcane Shot, Steady Shot, Concussive Shot, Steady Shot, Steady Shot

Hunter 3:
/assist focus
/castsequence reset=target: Viper Sting, Arcane Shot, Steady Shot, Steady Shot, Concussive Shot, Steady Shot

Hunter 4:
/assist focus
/castsequence reset=target: Viper Sting, Arcane Shot, Steady Shot, Steady Shot, Steady Shot, Concussive Shot

I'm gonna try this on my hunters, haven't just yet, so let me know if it works out well without pulling aggro. This is similar to my 73 BM Hunter I use for his DPS rotation when soloing, just modified a bit.
Another thing you could try is putting the Concussive Shot, Steady shot macro rotation in it's own macro on a separate button, so incase you wanna use this on a boss, one toon ain't standing there getting the error message saying "That Spell is not Ready". But for small mobs, they should be dead in less than 10seconds with this.

Be mindful that if you cast Hunter's Mark, you could end up increasing your chances of pulling aggro off your bears as well, but if you want to us it on mobs, this macro might work:

Hunter 1:
/targetenemy
/cast Hunter's Mark

Hunter 2:
/targetenemy
/targetenemy
/cast Hunter's Mark

Hunter 3:
/targetenemy
/targetenemy
/targetenemy
/cast Hunter's Mark

Hunter 4:
/targetenemy
/targetenemy
/targetenemy
/targetenemy
/cast Hunter's Mark

Make sure you hit your /assist focus button first so you don't end up pulling something that's further than you intended to pull. Since HM has a long range on it, chances are, this will cast on mobs out of shooting range you don't mean to tag yet. Good thing tho, this won't start up a fight.

Armory was down while typing this, but once it's back up, my main hunter is Brummly over on Earthen Ring. Talent spec and glyphs are being applied the same way to my hunter party I'm working on. Gonna respec one of the trees to a Surv/MM for max DPS for the instant shots for PvP once they all reach the same level. Priest will be parked up at that point. My hunters are intended to be one of my end-game PvP teams. Not too worried about instances for them unless it's a 10-25man.