Hello,
jPlayer can do its part... You are really asking about jQuery and
JavaScript in general. A simple piece of jQuery can make an AJAX call
to the XML files directly and then again use jQuery to read the XML
info and populate a playlist in the browser.
http://think2loud.com/reading-xml-with-jquery/
It sounds like you'll be reading in an XML file that contains URLs to
the Playlist XML files. Anyway, you would need to know the URL of the
playlist XML so that you could read it in.
Best regards,
Mark P.