I love mixed groups and wouldn't do it differently. However, I'm only running three at the moment (prot pally, bm hunter and elem shaman). I love it.

For PvE I've simplified it down to some macros for pre pull (buffing and totems), a spam macro for dps in combat (includes, tanking rotation), a macro or two for healing up the group and a "oh crap" macro (DI the shaman, feign death).

For boss fights I rebind my dps spam key on my elemental shaman to a healing macro that looks like this
/castsequence [target=focus] Chain Heal, Water Shield

Water Shield? Yes, water shield. Since I'm spamming I don't necessarily want to spam chain heals as I might not need that much healing so I add the appropriate number of Water Shield casts (since they cost no mana) to invoke the GCD a few times and space out the chain heals. That way I can just spam away.