I just made another thread about how I set mine up today: Effective Multitarget Healing

I tried seperate buttons for each but found it a bit messy. My other idea was having my priest use my target for healing (or just healed me if no target/harmful target) but it meant I had to stop attacking > target party member > wait out target delay > finally heal

The macro for the second way was /cast [target=name-target, help] [target=name] rejuvenation (replace name with your mains name or use focus if thats how your other stuff is setup.

I like my current way better though