The Virtual Local Area Network (VLAN) technology is one of the hottest areas of networking systems. A VLAN is a logical rather than physical connection that allows network devices to be combined as "virtual LANs". By this characteristic, VLAN segment the network into different broadcast domains so that packets are only delivered between ports that are combined for the same VLAN. Wireless ad hoc networks also have the flexibility to collect more than two devices equipped with wireless communication and networking capability. The communications would be needed for some wireless devices but not all devices in an ad hoc network. So an ad hoc network needs to form multiple-group as "virtual LANs" to ensure reasonable performance and security. In this paper we propose a secure VLAN construction protocol (SVCP) in wireless ad hoc networks. For eliminating broadcast drawback, source node will serve as a temporary agent to form a VLAN which generates a group key for secure communications.