Disc priest mouseover macro problem

ok so i was messing around with macros for my Disc Priest to minimize buttons on my action bar, this macro

#showtooltip
/cast [harm]Smite; [target=mouseover,harm]Smite;[target=mouseover,help] Greater Heal; [help] Greater Heal; Greater Heal

will cast smite if my target is an enemy, smite if my mouseover is an enemy, Gheal if my target is friendly, GHeal if my mouseover is friendly, Gheal on my mouseover but i have a target, and if i dont have a target will cast Gheal on me. my question is, how can i make it to work so if i have i have a enemy target but i mouseover a party/raid member to cast Gheal
thanks