This is exactly my question and dilema-> I believe that the child *is* hierarchly placed within the parent and that the responsibility should only be the parent's. And thus, while implementation is not a difficult situation as far as any of the 3 suggestions from jdporter's comments, the usage of redundancy in just the parent or partly in the child seem extra.

I believe I will brute force the results currently, but probably be forced to provide a lookup hash in the parent for efficiency.