How cool would this be? Well, unless you are the guy with the full battery and everyone is leeching off you.
Thus, if you find multiple devices where one is plugged to a socket and one having high Wifi signal strength among other, you can select them. Yeah one more thing, one paragraph of the description mentions preventing a device from supplying electricity wirelessly if it is on battery power. Thus, a device should be connected to a wall socket or may have considerable battery left to send electricity wirelessly.