The Only Way Is...
To rip the files you want into a single .mp3 file. You can find out how to do this at many rip app sites. I tried it with making a .pls and .m3u playlist (did not work) and renaming both to .mp3 and, everytime got invalid resource even though .pls works with my .mp3s (on-demand works for single files) but. I'll try using a ripped playlist as suggested when I have time. Hope this helps!