Help me write my priest's main pvp macro!

Hey guys, for the longest time, i have had my priest use "Circle of Healing" On all my guys' lightning bolt button. It has served me well up to this point, but I think it's nigh time to create a more (or less) "intelligent" macro, rather than mindless COH spam.

I want my priest to do a random one of several "useful" spells, possibly with preference to Circle of healing.

A few questions I need to know before I get started.

With the castrandom command, are you able to use different criteria for each spell, for example

/castrandom [target=focustarget] Hex of Weakness, [target=focus] Prayer of Mending, [Target = Focus] Power Word: Shield, [Target = AngelD] Prayer of Mending

Or am I forced to use the same critera for all spells? For example

/tar Focus
/Assist
/castrandom Hex of Weakness, Prayer of Mending, Power Word: Shield, Circle of Healing, Circle of Healing, Circle of Healing, dispel, Smite, Holy Fire, Shadow Word: Pain

Since they are not all Helpful or Harmful spells, but a mix of both, I couldn't do "target = focustarget" for all of them. I have to assist the main and then when i cast a helpful spell, it will automatically self-cast.

To reiterate, this macro will be bound to my other guys' Lightning Bolt button (which is the one button that sees the most use). I'm hoping that the random factor will add to the "fun factor", although it may get frustrating if i REALLY want to get all my guys' healed rather than all that other stuff... I find that my priest often tends to spam COH when no one needs healing, and it ends up getting mostly wasted.