[SR-Users] Best practice/routing block for TCP connection errors to UAC?

HI SR-Users Scenario: clients registered by TCP/TLS dropping off the network, kamailio stil thinks the client is registered and relays the INTIVE. The error occurs at the TCP layer so no failure route is called. ERROR: <core> [core/tcp_main.c:2690]: tcpconn_1st_send(): connect 127.0.0.1:48338 failed (RST) Connection refused ERROR: <core> [core/tcp_main.c:2700]: tcpconn_1st_send(): 127.0.0.1:48338: connect & send for 0x7f5494e906c0 failed: Connection refused (111) ERROR: tm [../../core/forward.h:251]: msg_send_buffer(): tcp_send failed WARNING: tm [t_fwd.c:1567]: t_send_branch(): sending request on branch 0 failed ERROR: sl [sl_funcs.c:362]: sl_reply_error(): stateless error reply used: I'm terribly sorry, server error occurred (1/SL) I want to send the caller instead a graceful failure route type message as if the callee is not registered (404/486/603/408 type) but don't understand how to hook a routing block for TCP errors. Anthony