The contents of your hashes increasingly looking like they belong in a database, and if stored as one, the answers to your questions are all database queries.

Please consider something like SQLite, which is a single-file easy-to-use database in ONE module. This will separate the data from your program, making it a lot more scalable, and easier to maintain (besides solving your current querying problems).

Yes - there will be a learning curve, but, believe me, you are header in that direction anyway.

If your organization already uses a database technology, you may prefer using that over SQLite.