Attack or Heal based on key "modifier"?

[thinus]

I have been looking for a macro that uses CTRL and SHIFT key as a modifiers that does 2 things:

1. Using Ctrl, cast spell on my main's target
2. Using Shift, cast a healing spell on my main.

The macros that I have seen have only been able to use the same target...can I set up a modifier macro that switches target?

My current Lightning Bolt macro:

/cast [mod:shift, target=Borck] Healing Wave; [target=focustarget, harm][harm] Lightning Bolt

If SHIFT is held down that macro will heal Borck, otherwise it will cast Lightning Bolt on the focustarget if it is an enemy else on target if it is an enemy.