OK, I'll try to explain it better.

Let's say that "Keep Talking" appears in a number of playlists (or subplaylists)

"Division Bell"
"Pink Floyd"
"By Artist"
"By Genre"
"Rock"
"Classic Rock"

Now, all of those playlists except "Division Bell" have the "Randomize" function enabled. (If I'm actively selecting an album, I want to hear it straight through).

So, I'm listening to "Keep Talking" and decide, say, "I'm in a _______ mood", it'd be nice to be able to change my "current playlist" to "some other playlist containing this song."

This might mean "let's hear the rest of this album", "throw me in the Floyd playlist", "throw me in the Rock playlist", "throw me in the Classic Rock playlist", or (if I'm tired of floyd-exclusivity) "throw me in the By Artist playlist" [which for me is the 'big master playlist containing everything that isn't an audio-book/spoken-word track']

Does that make it a little clearer what I'm looking for? Not necessarily that I want to be dropped in the "closest playlist", but that I might want to use some other related playlist.

D