Is is possible to explicitly flag an object from a persistent collection not to be persisted with the others in the collection?

I have a parent-child relationship where I want to add a new child that must not be persisted with the rest of the children. This alltimes transient child is my proxy to an external data store (maybe a database, maybe in memory, etc).

By being able to mix persistable and non-persistable children I am able to simplify my POJO object model somewhat.

any thoughts?

thanks,

--yuri