Does that mean that each end point will be in common with up to four devices, all trying independently to discover and identify each other? That strikes me as a very difficult approach to make work. I'd say you have a far greater chance of success if you put contacts on each face of the cube. I'd look for a solution which used asymmetrical contact positions to make it possible to know which contact was which, so that the 'discovery' part only had to establish a handshake between the two devices (that could be achieved by a collision detection/random backoff algorithm).