The interchange of data between client and heterogeneous sources requires an efficient and dynamic approach to mediation. Our framework features three layers of mediators: presence, integration, and homogenization. On arrival of a request for data exchange, a session initiation server forks to the mediator group to elect one mediator as global presence mediator that is responsible for data caching and service provision. Using Distributed Hash Table (DHT), the presence mediator dispatches the data stream request to other mediators and tracks down to the source, which is then integrated and connected to the client in a user-relevant way. Our mediation process is adaptive and dynamic upon the user request and takes QoS factors into consideration.