A P106 is a 1060 with no video outs. As far as the limitation goes on the m/b im not sure exactly why ASUS ended up with that setup. Couldve been on purpose or the limitation is created by components on the m/b or there just isnt physically enough space on the m/b for needed components to support 6 more true GPU's.
Stop trolling, you are not helping, there is nothing to do physically with the motherboard.
Where in my quote did I say anything about "doing something with the m/b"? Now whos the troll?