The only problem is that once it's playing the tracks, the empeg has no knowledge of playlists.
For example, when you tell it to play a portion of the tree, it uses the playlist information to generate the initial list of tracks. But after that, all it knows is "here's a list of tracks, beginning to end". Even if there was a button to skip to the next playlist, it has no way of knowing which of those tracks signifies the beginning of another playlist.
Although a variation on the Tweak Order buttons might be a workable solution: How about this?: Holding down the Artist button goes to Next Artist. Holding down the Album button goes to Next Album. It still wouldn't know the playlist structure, but in a properly organized sequential playlist, it could produce the same result: simply scroll through the list until it hits a track with a differing artist or album.
There was another request on the BBS for the exact opposite behavior in the case of the "hold tweak" button, so this would be contrary to that. Unless it behaved one way when shuffled and the other way when sequential... hmm....
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Tony Fabris