1. Ancestral property is defined as the property flow of title of which has not been interrupted for four generations i.e. from great grandfather to great grandchildren through any deed of conveyance or will. Mostly inherited properties are confused as ancestral properties.
2. If the property is ancestral property, then all of the great grand children of your great grandfather shall have to register a Release Deed in favour of your Aunts . If all of you stay in the USA, then the said Release Deed can be registered before the Appropriate Officer of your local Indian Consulate which is considered as an extended part of India.
3. If the said property was inherited by your father, then you, being his children, have no right, title or interest on the said property.
4. So, there is no requirement for your registering ant release deed in connection with the said property which is not owned by you.