Splitting export into sections for 360 VR screen

I'm working on a 360, stereoscopic timeline that will be played out by 6 PC's onto an 360 LED screen. I'll need to split the master 12816px x 4096px timeline up into x12 (2136x2048px each). The stereo will be top/bottom. Is there any way of doing this easily in Premiere or other software? (I'm not creating the stereo, that's  been shot in-camera). A colleague has a probable solution using a script for FFmpeg but avoiding rendering out the huge master in one piece would be good!