You can also use <stparty> <stpc> so you don't need a seperate macro for each pt member. Also <stenemy> <stenmity> <stnpc> for reverse targeting, useful for healing the person with the most hate.

A quick way to heal the person with highest aggro on a mob:
/assist <stenemy>
/wait 1
/ac "Cur[e/a]" <t>

<p1> is of course assuming that it's a person that's targeting your primary mob
<stparty> gives a bit more flexibility in