I just dinged L30 last night on GLA. It seems that every dungeon I run, there are several encounters where the healer pulls aggro (usually when there are three mobs).

I mark the targets and use Shield Lob as I run in. When I get to the mobs, I use Flash. I then use RoH combo on the current mob, with a Flash after every RoH. While I'm doing this, I lose aggro on one of the others, which makes a mad dash for the healer.

Should I break up the RoH combo so that each individual attack hits a different target?