Alcatech BPM Studio Gastro (Score 2, Informative)

BPM Studio Gastro Can output 6 independent mp3 streams with a suitable sound card(s):

http://www.alcatech.com/

I've been happily using their DJ software for years.

from the website:

The BPM Studio Gastro Features

Sound management from one central system
Arrange different playlists with the music of your choice and
direct them to each of the 6 areas.
Control your playlists, volume and sound needs for any area
in realtime.
Intelligent playlists
(store titles in any order, sort and rearrange them anytime)
Archiving of several 10.000 titles possible
Comprehensive drag & drop support