Used to mark collections for multi-tenancy when the commercial multi-tenant module is loaded. This is only necessary
when it's known the collection may contain members from more than one site. The most common case for this is when
the containing entity does not belong to a particular site (site discriminator is null) and a number of collection
members from different sites reference this containing entity. This is not a common circumstance and this annotation
is not normally used. Please note that collections marked with this annotation do not benefit from collection caching.