A method determines the relative locations of wirelessly controllable service device nodes and switching control nodes within a building. At least some of the service device nodes are located in different rooms of the building and should be allocated to switching control nodes on a room-specific basis. Wireless communication is established between the nodes to determine relative spatial positions of selected nodes using received signal strength indication (RSSI) values indicative of a distance of separation between two communicating nodes. The service device nodes are then grouped into two or more groups, a first group corresponding to service device nodes in one room and a second group corresponding to service device nodes in a second room, based on spatial distribution of the service device nodes as indicated by the RSSI values. The service device nodes of each group are then allocated to at least one associated switching control node.