Selecting players in your party can be done easily enough with the up/down controller buttons, and who gets selected by the left/right controller buttons is configurable. If you're healing someplace like a big FATE where you want to heal players who are NOT in your party, then just switch your left/right buttons to selecting players. Then when you're doing DPS, switch those left/right buttons to selecting enemies. I have my PS3 set up to use L1+square to put me in "Enemies" targeting mode, L1+circle to put me in "Friends" mode, and L1+triangle to put me in "All" mode. (That's configured in the Targeting section of Character Settings.) That way you can easily switch your targeting mode around according to what you want to do at the time.