The provision of innovating multimedia services is a high priority for service providers. Due to the the high traffic volume characteristics of multimedia content, decentralised services are a desired solution for multimedia scenarios. Based on the ongoing work of the IETF P2PSIP WG this paper defines a simple way to interconnect different domains using on peer-to-peer technology. The objective is to provide connectivity between users of different domains and allow decentralised multimedia services to be placed where they can be provided most effectively. Furthermore, the routing performance and routing state is analysed for the proposed hierarchical DHT overlay architecture.