Create a YEAR LIMITER for the player interface.  The user sets a low year and a 
high year.  With the plugin filter active, any additions to the player playlist 
(using play or add) have to pass the year test.  Any tracks outside the 
limiting range would not make it to the playlist (or alternatively, the tracks 
could be added to the playlist but skipped during playback if better for server 
performance).  This feature would allow for more dynamic playlists as multiple 
genres could be added to the playlist but only those from a specific era would 
be played (i.e late 1970's, mid 1990's, etc.).