Reversing Life Drain

Enfo's did it on the Empath, so it is possible, unless they triggered it out.

So does anyone know how to reverse life drain so that the hero can target an ally hero to give their life to them? The targets allowed seem to be hardcoded into the game. Is it possible by just tweaking the skill, or do I have to reconstruct it with triggers?

Gameplay constants?

I found the boolean value that allows life drain to transfer, thanks.

I looked in gameplay constants before, but seemed to skip over that somehow. :P