1. A computer-implemented method for maintaining group membership records, at least a portion of the method being performed by a computing device comprising at least one processor, the method comprising: maintaining a record of group memberships for a membership hierarchy, the membership record identifying a direct relationship between a first object and a second object in the membership hierarchy; receiving a membership update indicating that, as of a first point in time, a direct relationship between the second object and a third object changed; updating the record of group memberships to reflect the change in the relationship between the second object and the third object; deducing, based on the membership update and the record of group memberships, a change in an indirect relationship between the first object and the third object as of the first point in time; using the record of group memberships, the updated change in the direct relationship between the second and third objects, and the deduced change in the indirect relationship between the first and third objects to provide a view of object relationships within the membership hierarchy as the object relationships exist at the first point in time; maintaining a historical record of group memberships as they existed before the first point in time.