Unfortunately not. There are no Brightsign models that have six HDMI outputs. The XC5 range can handle multiple HDMI outputs per player:
https://www.brightsign.biz/brightsign-players/series-5/xc5/
From a cost point you might be better off using 6 LS units.
You would be looking at syncing multiple brightsigns linked together on a local network.
If you want frame accurate, I would recommend setting up a brightwall presentation. If you dont mind being a couple of frames out, I'd go for a master/slave arrangement.
https://support.brightsign.biz/hc/en-us/articles/218067417-Synchronization-options
