Built-in regeneration? General Support? It's unlikely that such tricks will work in multiplayer (combat scripts don't work).

This isn't a combat script. It's a buff embedded in the skill.
For example, General Support looks like this:

SKILLTYPE_SPECIAL_PERK
HERO_CLASS_BARBARIAN

SPELL_EFFECT_POWERFULL_BLOW


As a result, the entire army of a hero with this skill starts the battle with General Support applied to it.

Thus, you can apply almost all spells, as well as many specialization and skill effects, to skills.
It's amusing to see General Antimagic (applied at the basic level) on the entire Orc army.

P.S. Replay with General Support.