Hi Francis,
Something to consider - what format compression - FLAC or MP3 - have you used on the B2. If FLAC, does the car system play FLAC files?
You can use a Playlist to copy selected Albums or Tracks to and then use the 'Export Playlists' option in the Playlist menu, to send these to a USB memory stick.
Alternatively you can plug the backup drive into your computer and copy the Albums/Tracks you want to a memory stick. You can also do this using NAS mode to directly copy from the B2 - might be a bit slower, depending on the WiFi speed.
Paul
Brennan Support.