Folder-like tagging system?

I am currently having a question. There is a group, which is consisted of different units. I want to find out a way to make the tags of the songs together form a folder-like(???) system on the computer. Like inside the main group are the units, and inside the units are the songs of the units. It can also be like that for the genres, like inside pop there is tons of other kinds of dream pop, bubblegum pop, ... I'm not sure if that is possible, but if anyone has a solution, I would be grateful!

Thanks for helping!

Can you check whether this is the answer to your question?

I don't think it is. I'm asking this because I want the files to have that folder-like order on my iPod. I don't think this would make them that way.

Can you provide some real life examples?

I simply cannot understand what it is that you are after

Are you sure that an iPod supports a folder-like order?
Have you ever seen such an order and can you tell what such an entry looks like?

To be quite honest: I do not think that there is any player that supports a hierarchical arrangement of genres like a folder tree.