Nested genre tags

I just wonder about your hierarchy or taxonomy.
I can see, how you could change your genre tags with actions, like poster said, or even more elaborat, but in the end you would still have to build many, many different actions.
How big will your taxonomy be, how many positions? You would have to define genre cluster for every possibility of genre, which gernre triggers which extra genre... That looks like a lot of work, even before you can build actions or think about other tools to do the job.
If you would build a taxonomy, would be very much interested to see it.

After defining my taxonomy, I guess I would do it as poster said. Depending on the accuracy of your existing genre tags, you could filter or would have to search your collection manually. Thank mark all the relevant songs and tag them with an action.