Birthsiblings support groups

Does anyone know of any groups out there that birthsiblings can connect with? There is so much support for the birthmother and adoptee in a reunion situation but the other parts of the family tend to get lost in the shuffle. Me and my siblings are frankly worn out of hearing all our mother's woes about giving up her son for adoption over 30 years ago. It is hard to talk to others about the situation because they can't tell us what is normal and how to deal with a manic and emotional parent still dealing with reunion issues and adoption issues of the past. Any help would be greatly appreciated.