I've got some non-soup playlists in a hierarchy like so:

Electronic -> Vocal -> Fast
Electronic -> Vocal -> Slow
Electronic -> Instrumental -> Fast
Electronic -> Instrumental -> Slow

is there any way of constructing a playlist based on an advanced search, which combines the two "slow" playlists together and the two "fast" playlists together? The only solution I've come up with so far is to add "slow" or "fast" to the comments field and do it that way, but is there a more elegant solution?