A traffic network having a wired as well as a wireless network backbone is managed. The wireless network backbone has relay nodes having wireless routers, some acting as gateways to the wired backbone network and some as relay bridge routers for access network access. A management system has a logical multilevel hierarchical network overlying the traffic network. It is adapted to use the relay nodes as management stations. It performs a grouping process by arranging network nodes, including the relay nodes, in groups, each with a cluster head, on different hierarchical levels. A grouping controller controls the grouping and allocation of cluster heads based on a number of grouping constraints given by one or more criteria to be fulfilled at each hierarchical level. The criteria are calculated based on given metrics, the constraints are modeled, and fulfillment of the constraints is verified at each hierarchical level.