This paper concerns how the virtual subnet mechanism is engaged with the hierarchical architecture in ad hoc networks. The employment of virtual subnets performed at the Data Link Layer can prevent the reveal of broadcast storm and further improve the efficiency of traffic between members of specific group in ad hoc networks. A convenient method is proposed to select crucial backbone nodes which will furnish the ability of filtering frames in virtual subnet against the unnecessary flooding, termed CVA (Clustering with Virtual subnets support Algorithm). The chosen nodes include two different types, station nodes and port nodes, which act functionally as the switch and the ports of the switch to filter frames, respectively. We evaluate CVA with the metrics of average nodes in the backbone and duration of the protocols. The simulation result manifests the proper performance while supporting the virtual subnets in ad hoc networks.