If you're using Keyclone I would just use this on round robin.
Code:
/cast [target=focustarget] Lay on Hands
If you don't use Keyclone, I'm sure most of the other programs have a similar feature.

However that's more for emergency healing. For just healing in general I use this on my pally team

Code:
#showtooltip
/use [modifier:shift, target=player] flash of light; [modifier:ctrl, target=player] holy light; [target=focus] flash of light
Pressing the button casts 5x FoL on your focus
Button + Shift = FoL on each individual toon
Button + Ctrl = HL on each individual toon

If you're interested in more macros, I got a list of most of the macros I use on my 5x pally team listed in this thread. [How-To] 5x Paladin Discussion