Do the two Org vDCs use different storage profiles? If so, it's easy ... set the default profile on the catalog to the new one and then copy objects into the catalog again. this will do the migration.
Otherwise, the catalog will use "any available" profile to the organization and just dump the vApp/Media into any datastore.
If they use the same storage profile, you can consolidate and then storage vmotion them to any other datastore in the same storage profile.