The three elites(/champions?) you were talking about are not a boss, but just some tough mobs to fight on the way to the last boss. Pulling three at a time is usually a wipe, unless your group is overleveled or the group is overall solid *and* the healer is really good.
You should be able to pull just one at a time, or at most two. Wait for the walking ones to be close, and pull them separately, then try just pulling the nearest one, etc.
Ah, yes, that part. In a lot of groups that I've been with through that flashpoint, near the end there someone will typically tie up an enemy to make them easier to deal with. An Operative or an Assassin can use a stealth stun to tie one up without initiating combat and then you can just skip the group if you want. (Just make sure nothing goes wrong with the final boss fight because nobody that falls stands a chance of reviving and running back to the fight if there are still enemies in the way.) Otherwise you'll have to fight them and it's divide and conquer. Somebody puts one of the enemies out of the fight for 60 seconds and you use that time to take out the other one first. (Try to deal with the one that wanders through separately as well if you can. Wait until you can take him on when he won't be the same fight as those two.)
Divide and conquer can be a useful strategy in all sorts of tough group fights. Try to be aware of which classes have access to which stuns so you know exactly how much your team can tie up. (We usually specifically talk about the 60 second stuns here. There are plenty of short stuns too but those will usually get mixed in with combat instead of keeping an enemy out of combat completely.) Anything that can be tied up at the start of a fight is one less danger to worry about for the first 60 seconds (so long as nobody attacks it or catches it with an area attack).
but the whole fight the sith sorcer kept calling me an idiot
Going back to this story, the Sorceror could have tied one of the enemies up in a whirlwind. I'd assume that that was probably his intention before the fight started. And then either there was too much going on to be sure that he could have used it without someone immediately waking the enemy up or he did use it and the enemy was immediately woken up. (Either way, it was your fault but he should have explained afterwards "I had one tied up, don't break my cc". Get through it and then explain that it could have been much easier, because that time he spent chewing you out in the middle of battle was time spent not contributing to the fight which only would have helped to make a bad situation worse.)
a little trouble establishing aggro from a sith sorcerer but he kept attacking things I have no even hit yet but i just grappled them from him to get aggro.
If he was really attacking early that's his mistake. But if he was really tying an enemy up in a whirlwind though and you thought it was an attack (which I suspect is what was really happening) that's your mistake, and you may have been disrupting his efforts to make fights easier through the entire flashpoint by screwing up his stuns.
Of course maybe he could have communicated that better and he probably should have spoken up about it earlier than the last group before the final boss. He could have clarified that he was going to be tying a target up in each fight. He could have marked his target and said for nobody to attack that target (make it a general reminder for everyone even if the issue was only with you).