Previous studies have proved that the performance of IEEE 802.11 protocol is poor when used as a platform to implement multihop ad-hoc networks. We elaborate on the negative behavior caused by having multiple overlapping IBSSs (independent basic service sets) operating on the same frequency channel in an 802.11 ad-hoc network. Then we propose an overlay algorithm on top of 802.11 to help discipline the interaction of overlapping IBSSs with one or more stations in the overlap zone. Such algorithm enhances the support of multihopping in 802.11 ad-hoc mode. Performance analysis and simulation results of this algorithm show noticeable improvement in overall system throughput as well as stability.