I'm not going to invite an aunt to a bbq and create a rift in the family
Why would you not invite them?
I want to keep my family outside my small social groups. Everyone hates that bitch.
You should always include your family, even if they are terrible. However, it's fine to exclude them if they are so bad that everyone hates them and they destroy your family.
She is that bad but everyone else does not know it yet.
You should think this over carefully. Maybe you have another family member you an talk to because if a family member if hurtful you do not need to include them in your events.