For my melee toons, I have a sperate IWT button as well. Like my most basic setup is using buttons 1, 2, 3 on the keyboard.
Those action target groups are huge.
I also have a Everyone drop follow key, as well as a JUST ranged drop follow key.
1 = aoe dps rotation for all [heals aoe as well]
2= single target dps rotation [single target heals as well]
3= is my melee only IWT button. So to keep them with my tank as i round up or if I need to move due to a mechanic of the fight.