You say you have no PC family, I would gladly accept you to be my family, but you will have 2 sisters in law an a little sister? is that okay? I am only telling you that if you want to be related to them, but you can still relate to me and no one else, but ask them first.
If you decide to relate to all, you would have
Little/big sister Chef30
Sister-in-Law: Shinysweety (My Little sister's Pair)
Sister-in-Law: Roleplaygirl10 (My Pair)