I need a castsequence modifier healing macro. I don't know if it's possible, and if not I'll use three separate castsequence macros. Like this:

I push say...4 and my main shaman heals himself, I push it again, and shaman 2 heals him, another press and shaman 3 heals him.

With shift-4 main heals shaman 2, another press and shaman 2 heals himself, third press and third shaman heals him.

With ctrl-4 main heals shaman 3, with a second press shaman 2 heals shaman 3, with a third 3 heals himself.