[Kaperstone]

Well, my guess is that he means that he wants to find other PC's connected to the same router/modem using a certain PC on the network or any other way to find other PC's somehow related to a certain person using one of the PC's that a certain person owns, which in that case, only possible if the IP's match or somehow through geoip (I think?), other than that I can only think of hacking his PC.