Computerized methods, systems, and computer-readable media for promoting cooperation between a first and second virtual network overlay (“overlay”) are provided. The first overlay is governed by a first authority domain and includes members assigned virtual IP addresses from a first address range. The second overlay is governed by a second authority domain, which is associated with a second federation mechanism, for negotiating on behalf of the second overlay. The second federation mechanism is capable of negotiating with, or soliciting delegation of authority from, a first federation mechanism that is associated with the first authority domain. When negotiations are successful or authority is delegated, the second federation mechanism establishes a communication link between the second overlay and the first overlay or joins a member of the second overlay to the first overlay. Joining involves allocating a guest IP address from the first address range to the member.