[Users] Force MediaProxy only in PSTN GW

Dear List, I'm deleted many things in OpenSER and reconfigured it : * clients behind ADSL Routers so NATted clients, since we apply for forwarding for port 5060 in each modem, they can register with SER and they can talk with each others, voice traffic does not pass through OpenSER which is good and preferred :) * i have already set up mediaproxy but stopped it to make this experiment with OpenSER, but i will start it again for case : If a client needs to call PSTN, the voice should go from client to OpenSER (no MediaProxy) and from OpenSER to PSTN (MediaProxy) Is it possible to force SER to use MediaProxy just for case of PSTN calls simply ? Thanks, Ozan