[BNM] representing an OR aggregate/composite relation in UML class diagrams

[Jon Bedworth]

Hi BNM,

I am wondering if there is a UML formalism for representing the fact that
something may contain one thing OR another. So, for example, a container may
represent one kind of item, or another.

Is it simply that I just indicate 2 aggregate/composite relations between
the container and each type of item (which would just say that the container
could contain either type, or both), or can I specifically notate that the
relation is one OR the other (but not both)?

Is this possible?

Thanks

Jon