Actually I got it to work! The structure and your comments made it very easy to follow. Thanks a bunch.

The only quirk that I ran into was that the bottom tier of the hash was a list instead of a hash entry. I had wanted to use a hash if only to squirrel away a data value upon retrieval. As a workaround, I just created a separate HoH for that purpose. (Now that I think about it, I could have created an array for this).