How do I make the game realize a new hero should be unique?

When I build a new hero in my mod, it understands that it gets only one per hall upgrade, and it understands that it can't have more than 4 total heroes (my mod has 4 instead of 3), but it doesn't understand it shouldn't allow the same new hero over and over, thus I could build 4 pit lords.

What do I need to do to limit new heroes to 1 per player? (this is for custom mpq; no map triggers)

well for custom MPQ you should edit Blizzard.j I think. Look for melee intilization, and change their hero values for SetPlayerMaxTechAllowed for yours.

This is basicly the same as triggers, though Blizzard.j is read for ALL maps.

I set everything I found in blizzard.j; must be something else.

Edit:

never mind; I found the function you were talking about in blizzard.j. Thanks a bunch!