Hello, I've got a mapping problem

I've got two objects
- E (element)
- S (Sub element)

E has a collection of S but the relation between E and S is based on an interval of validity.

In details :
- E has a "code" that is not necessary unique.
- S has a "code_start" and "code_end" that determines if it is valid for a specific E.

So for one E I want to retrieve every S where :
S.code_start <= E.code < S.code_end
and store all the S in a collection of E

The idea is to write this relation directly in the mapping.
The database exists and cannot be changed, but for the rest every solution that works is welcome !!

Thanks

I thx, you can use formula in your property mapping.
http://www.hibernate.org/hib_docs/reference/en/html_single/#mapping-declaration-property

The formula attribute isn't a solution because I want a separate mapping for E and S to use the two objects separatly.
So I have to use a one to many association and I don't see how to make the join with an SQL request.

My first idea was to use a compositeCustomType on the columns code_start end code_end but I'm not sure if it is possible.