I agree:   you should step back now and review your entire approach here. (Follow that link for “XY problem...”)

The bucket of any hash or list can contain one value... but that “value” can be a reference to anything. Therefore, while you do not properly have “hashes of hashes,” hashes can contain hashrefs.

Nevertheless, if you are now contemplating “funky data structures,” as a rule of thumb it is wise to step back and reconsider just where you are intending to arrive, and whether the path that you have selected is really the right one.