I’ll be honest, this is confusing as hell, so I might be misunderstanding.
I think it’s a little hypocritical that you want it to be a chill, no drama space with the bros, but you also want to exclude a girl because you see her as competition for the guy you like who is in this group.
I understand you had a bad experience with her, but you said that the guys don’t know that. From their perspective, you’re just excluding other girls for no other reasons than seemingly to be the only girl in the group and perhaps to have exclusive access to your crush.
If you don’t mind me asking, why don’t you like this other girl? Was she mean to you?