I've done a fair ammount of searching but can't seem to find this.

What I'm looking for is a simple macro to swap between my focus and my last target and back and forth as needed.

IE:
Focus my healer, target hostile mob; Then I can swap back and forth for things like Intervene on the healer and back to the mob for tanking.

Failing something of this nature I suppose I could use an intervene macro but would prefer not to.

Anyone have any ideas?