There is an order. Only one can be hurt while the others are up.
Just keep trying each one until it drops below 96% and then stick on it.
Stay off to the far right (if you look at the hill from the outside) because I never ever get adds but I always see them on the left side piling up.
There is no order, period.
Taslr (sp?) is a healer, so he heals.
Fibor (sp?) is an SK, but he has a lot of out going heals also, most of them are on himself, but I think he has 1 heal that hits others.
On EM, I target the main named and afk. Come back to a chest.
On HM, I kill Libmr, (kill adds to 75%), Taslr, Carsl, Necro, Fibor.
If you are having issues (on EM or HM), set up an auto target to do something like I do on HM.
Kill 1 mob off straight up (Limbr has the least HP and dies the quickest).
Then adds to ___%. This will depend on your AE dps. I don't mind having 2 waves up (8 adds on HM), but when the 3rd wave spawns, the 1st wave should already be dead. For me, that's about 80% (meaning I kill adds to 80% then switch off them).