Need some help with a custom boss problem

I have a custom enemy group on a story arc that I created which has specific bosses that fit into the storyline for each of the 3 missions. After you've defeated each boss, that's it, they are out of the picture. However, I've noticed a couple of times when I've run the arc with a cranked up difficulty that they've popped up on maps not as my main "defeat a boss" goal with all of the dialogue but just as a regular boss in an enemy group. It completely ruins the entire story because either you've killed them earlier in the arc and they should no longer exist or you end up beating them and then running into them again when they are actually supposed to be in the arc. Is there a way for me to restrict a custom boss from appearing elsewhere in a mission or on a map in a custom enemy group? I could add another generic boss to the custom enemy group but how will I be assured that the generic boss would be the boss selected from the possible bosses for an enemy group spawn?

the best way to solve that is to put the bosses you only want to spawn one time into their own enemy groups with the same name as the ones you normally have, but add maybe an extra space at the end so its still technically different

then in the normal enemy group just add in a different boss that can appear regularly

Ahhhhhhhhh, very nice. That sounds like a good solution. I'll try that and that should fix the problem! Thanks!