[SR-Users] Kamailio dispatcher module - keep alives

Hello there, I have a Kamailio server using dispatcher module to monitor several peers, some of them are in the same network, others are in an external network, for the peers that are in the external network kamailio has to send the OPTIONS(dispatcher keep alives) through another kamailio located in the border and acting as loadbalancer. If i set the dispatcher option "outbound_proxy" all SIP OPTIONS are sent to the outbound proxy configured and it isn't what i need, I need to have by some way a possibility to set outbound_proxy only for the peers that are located on the external network. How can I do that? Regards -- Cumprimentos José Seabra