Aggregations are implemented as "shared" aggregations in IBM® Rational® Rhapsody®, in that a part can be simultaneously aggregated by several wholes because it is not physically embedded inside any of them. Composition is an even stronger form of "non‑shared" aggregation, in which the part is embedded inside the whole and comes into begin and dies with its creation and destruction.
The rules for implementing aggregations (that are not compositions) as either pointers or containers depending on the multiplicity and ordering of the relation are the same for aggregations as for associations.