Baby only wants mom and dad!

My daughter has been doing the stranger anxiety thing for months now. She is so happy and independent when she is just with her dad, brother and I at home. But if we get around our families she does not want anything to do with anyone but us. She won't let them hold her and is whiney the entire time we are at there house. She has been around these people her whole life and knows them but doesn't want anything to do with them. My dad gets so sad cause he loves her so much and she won't let him touch her lol. I know this is a stage but it seems like it is never ending and is only getting worse. If we are at the store or restaurant she is happy and wants everyone's attention but just no one is allowed to touch her. And no I do not hold her all the time or anything like that, I let her do her own thing. Anyone else dealing with this?