Apparatus, and an associated method, by which to facilitate selection of with which network portion of a WLAN-cdma2000, or other multi-network radio communication system, that the mobile node should communicate. A parameter message is communicated to the mobile node. The parameter message includes indications, values of which are extracted from the message, buffered at a buffer, and subsequently accessed. A selector utilizes the accessed values to determine with which of the network portions that the mobile node shall communicate.