My team uses a holy pally for heals, my macros goes as follows: (doing this from work, might be some errors)

Numpad 9 (Fire Mage 1) /cast [target=pureundead] [modifier:lalt] Holy Light; [modifier:rctrl] Blessing of Protection; [modifier:rctrl] Clense; Flash of Light

Numpad 6 (Shadow Priest) /cast [target=purehorde] [modifier:lalt] Holy Light; [modifier:rctrl] Blessing of Protection; [modifier:rctrl] Clense; Flash of Light

Numpad 3 (Fire Mage 2) /cast [target=pureforsaken] [modifier:lalt] Holy Light; [modifier:rctrl] Blessing of Protection; [modifier:rctrl] Clense; Flash of Light

Numpad . (period) (Holy Pally) /cast [target=purebubble] [modifier:lalt] Holy Light; [modifier:rctrl] Blessing of Protection; [modifier:rctrl] Clense; Flash of Light

Numpad 0 (Prot Warrior) /cast [target=purezerker] [modifier:lalt] Holy Light; [modifier:rctrl] Blessing of Protection; [modifier:rctrl] Clense; Flash of Light

It's a lil complex, but all the healing uses only 5 keys. Also I have the mages/priest cast remove curse/dispel magic if any along with each heal. This keeps the group pretty clean.

Go Horde, Pure