Consider this example system consisting of the following resources: Family, Person and Role. A Family and Person has a many-many relationship and each family member has a certain "role". For example, a family may consist of persons with the following roles: a mother, a father and two children, but the parents may themselves have the role of child in their own parents' family. Thus, the family-person-role relationship is a composition of these three resources.
My question is this: with complete disregard of system internals and data-storage structures, would this relationship be considered a resource in terms of REST or meta information associated with one of the other resources?