1. A proxy server comprising: at least one computer processor; and at least one tangible computer-readable storage medium having instructions that, when executed by the at least one processor, cause the at least one processor to at least: determine that each of multiple wireless devices is associated with a predetermined vicinity; determine respective identification information corresponding to each of the wireless devices; and associate the respective identification information corresponding to the wireless devices to a dummy identification in response to determining that each of the wireless devices is associated with the predetermined vicinity.