Adoptive relative is against adoption

Some people don't accept it, and yes it hurts. It is hard to deal with if you have to associate with people like that - in the name of family peace. You have options already provided above. Personally, if I had to be in that situation seeing as she does not see you as real, would be to not acknowledge she exists either. Go in, hug/talk to everyone except her - and make it seem like you didn't see her in the room (takes skill and practice, or you can excuse yourself half way through and use the ladies room, take your coat off, or whatever and then just miss her again). When she speaks her words don't exist to you. Turn and speak to the person next to you about a different subject making eye contact. Don't make eye contact with her, and be the most outgoing self you are naturally, and have fun. Do it carefully so no one can accuse you of trying to make a production out of it - more like you just didn't know she was there and thought she opted out of attending. She will go home feeling the sting of not being real. Kind regards,Dickons