Bookmarking Playlists to pick up where you left off

I have a series of playlists I like to listen to, but it is a pain to switch between them on my Sansa (Express and Clip+) since if I leave my “News Podcasts” playlist to listen to a music or book on tape playlist I have to remember which file/timestamp I was at and navigate my way back to it.

It would be wonderful if the Sansa players would keep multiple bookmarks, one like it already does for when you power down so it resumes where you left off, but also another bookmark associated with each playlist on the device.  The playlist bookmarks would be updated when the Sansa is shut down like the main bookmark, but also when you navigate away from the playlist.  When selecting to return to a playlist, the Sansa player could provide an option to resume playing within that playlist from where you had left it.