Aaron–
Are you able to upgrade to 3.5.3? In 3.5.3, there is a new feature in Criteria Builder called Detached Criteria Builder that allows you to add subqueries as either projections or (in your case) as restrictions.
If you can’t upgrade, let me know. Before 3.5.3, I had a stand-alone version of this that integrated into the 3.5.2 Criteria Builder, and would be happy to share the strategy for using that.