I boxed those Cata dungeons. Back then my 3 DPS on my trinity team were all hunters. So aggro wasn't a problem.

If you want to do this right just have a toggle setup to disable broadcasting to the DPS. Usually part of a group assignment. If you drive from the tank or even the healer the DPS could be on follow while the tank gathers everything up. Then hit the toggle again once the tank has secured aggro.