If you finish of the strength as well I suppose you might not have that much time to spare, we simply had someone else pick up the second str if we ever had two up at once. We just had two players start below the courage as it spawned, and had the rest of our ranged (those suffering the most from movement) stay on the new set of rages and simply turn around and nuke the courage just as it reached the halfway line, with some short duration cc/roots on the rages. This was enough to kill the courage before it reached the tank and the rage set was just about dead when we the second spawn (and we didn't have amazing dps). We did end up with 2 str's for a while, but they are quite frankly a joke to deal with anyways. Admittedly dpsing the ragepack with half the dpsers gone could cause some issues if you don't have a lot of abilities to control them (but almost every setup has).
You can make your hunter soak two if needed detterence>readiness for next one > detterence. I wouldn't suggest it though because thats a big dps loss for him. If he's going to soak any though make sure he's glyphed for the reduced dmg on deterr.
Okay, the second set of rages, not sure why you are cc'ing them...yes the courage comes but you're only making it harder for yourself trying to kill four of them together when the third set spawns, especially since there isn't a hell of a lot going on and you have two extra people (the tanks) to help you. For as long as you are cc'ing that second set of rages, you guys are going to fall behind. Your rages need to die within a second or two of each other and you need to use knockbacks, roots etc, so things aren't chaotic. The trick to that is making sure you're ranged dps are there to greet them every time. Strengths are pretty much the lowest priority for everyone in your raid minus the rogue that is tanking them, as long as you dot it up and focus it when other things aren't going on, they're going to die just fine. But rages are by far the hardest thing to manage, and that is what is screwing you guys over right now.
What I would suggest for soaking order:
Rage 1: Hunter
Rage 2: Either of the tanks, they'll be busy with the bosses in a moment so don't waste someone else's cds that you may need later
Rage 3: Hunter again, deterrence will be up
Rage 4: Hunter could do it again using readiness and popping deterrence
Rage 5: CC these, and that's it the entire opening phase
Rage 6: Break the two cc's and this is when you want to kill them all together. If you kill them nice and tightly together and roughly at the same time, your hunter can soak them all/most of them so you probably want a backup soaker just in case
Strengths and courages: Your rogue can get every single strength spark using feint with the elusivness talent that decreases the damage further. That leaves plenty of options to soak the courages while still having one or two people left over as backups. The trick is to not waste CDs of people that can soak 2 or more sparks easily on just soaking one spark.
After you get through the first double add wave, rages soaking are pretty much handled by your hunter:
Rage 1: Hunter
Rage 2: CC
Rage 3: Hunter, and again, as there will be four you'll probably want someone else at the ready in case he is unable to get one. Strengths and courages will remain the same
In short, stop cc'ing the second that set of rages, and ensure you kill them together when you do kill them because your sparks are going all over. Once you do that, you're well on you're way to a kill.
A link to our kill video that uses the same basic strat. It's from our priests PoV and it's not the best kill ever but if you just watch the first few minutes you'll see what we did, and our dps is by no means amazing. But your rages and sparks are all over the place and your losing shitloads of dps. Get them under control.