If precision sync is not an issue, you can create your program streams in any editing platform, using one audio track, and a separate nested comp for each "screen". Then make output your playback files to your desired playback format, and just make sure you set it up to have identical pre-roll and enough tail end to not cut to a blue screen or no video signal when finished (add black).
As far as playback is concerned. I had a project we did 2 feeds, 3 screens, (L, R, Center). The sync was not frame critical, and we were able to get away with outputting our files to BD-R and using Blu-Ray players as source decks. Using the same brand Blu-Ray (Sony) Player, and a SINGLE remote control. Using one remote, allowed us to queue, stop, start, the program feeds, and the sync was near perfect.
If you need frame accurate, or field accurate, you will need a playback system of some sort. If using decks, as long as the decks have pre-roll and are frame accurate, you can sync them together and use a jog shuttle to control them.
Also Playback Pro is worth looking into: https://www.dtvideolabs.com A bit expensive, but it will do multscreen presentations, and is designed for live AV.
It all depends on how perfect your sync needs to be. One project we did used 2 20K Christie Projectors to shoot polarized (not active shutter) 3-D; just like in theaters. For that, we had to be field accurate.
Hope this helps.