Check out this Instructable by thomashollier
"A filmmaker friend approached me to design a display device that would allow her to display a video tryptic at the 2015 Venice Art Walk. The idea was to create a frame that would contain all the components necessary to play three different videos on three separate screens in perfect sync. It should be simple and should not need to be connected to a bunch of cables or computers. The goal was to hang it, plug it, turn it on and forget it… Oh, and did I mention it should not cost an arm and a leg?".
"Based on my previous tinkering activities, I felt that this project was within my reach and so I started researching parts. My first order was for 3 Raspberry Pi 2 mini computers, 3 replacement laptop LCD screens and the 3 driver boards they needed to be connected to the Pi’s HDMI output. Along with that, I got the various necessary AC adapters to power all this mess".
Have a look at the whole project at; http://www.instructables.com/id/Synced-video-tryptic-with-Raspberry-Pies-and-lapto/