Auto-Change playlist

[transientRbox]

What I'm trying to achieve in terms of playback:
1. Playlist a set of songs together  (such the medley on the Beatles Abbey Road).
2. Have other playlist of songs which I'd like to be contiguous.
3. As in Auto-Change directory I'd like to have No, Yes, Random

I would then generate playlists externally to cover the rest of the songs (probably python).

I would then be able to have a somewhat random playback, but with songs grouped together that I feel
should be together.

Is there a way to achieve this currently ?

Is there a limit on the number of playlists ?

Thanks