Necromancer: Summon skeletons of your choice

Greetings, I would like to know if it possible to modify this skill to summon only the type of skeletons you want. Also, if this is an easy/hard request to accomplish. Thank you for your time :).

Could probably be done via skill modifiers (one modifier per skeleton type), or if you e.g. always want mages, by editing the skill itself.

Yeah, that’s the idea. I only want archer skeletons. Well, it would be nice if someone is willing to do it ^^.