Hibernate version:2.0

What I'm trying to do is to eliminate rows that have expire date populated from a hierarchy using just standard mapping or HQL. For instance A1 has a collection of B1 and B1 has a collection of C1. If I get all of A1 I'd like the collection of B1's to be with out expired records, and all their collections of C1's to also be free of records with the expire date populated. Is there a way to do this with HQL?

It would have been good if I could have done it some way through the mapping so that any finder would not return expired records.

Thanks,
Dan