The increasing heterogeneity of end-user terminals as well as network access technologies leads to a demand to deliver media content adapted for possibly multiple and different end-user devices. Media adaptation performed on the server side has shown its limitations and on demand network side media adaptation, performed transparently for users and content providers emerges as a promising approach. Based on this concept, the proposed Smart MultimediA Routing and Transport (SMART) architecture, a novel overlay network solution designed within the Ambient Network project, will enable the transparent integration of advanced media processing modules into end-to-end media delivery paths. The required media processing modules need to be selected based on end-users requirements as well as Quality of Service (QoS) constraints defined by service providers. In this paper we propose a distributed hash table (DHT) based approach to support the selection and instantiation of Media Processing Modules to realise a Service Specific Overlay Network (SSON) for a network side media processing and adaptation.