Updated with functional Numpad1-5 party#-based healing system.

Not the cleanest, but it works.

The biggest drawback I've had so far is that using RDF randomizes the group order.
This can be fixed by sequentially removing people from group and adding them back in via correct order.

Note that this works only when the group is invited in the same order.
So you should create group from WoW1 which will make the group look like this, from WoW1:
Player=WoW1
Party1=WoW2
Party2=WoW3
Party3=WoW4
Party5=WoW5

After that - it doesnt matter which window you are controlling. FTL, whatever - hitting numpad1-5 will heal in perfect order:
Numpad1: Player (self)
Numpad2: Party1
Numpad3: Party2
etc...