[Users] Making OpenSER give up being man-in-the-middle?

[Juan Carlos Castro y Castro]

Hello, I'm using OpenSER to make load balancing among a bunch of 
Asterisk boxes. I whipped up a very simple script that works:

# module stuff goes before here
route{
        if (!mf_process_maxfwd_header("10")) {
                sl_send_reply("483","Too Many Hops");
                break;
        };
        if (msg:len >=  2048 ) {
                sl_send_reply("513", "Message too big");
                break;
        };

        route(1);
        break;
}

route[1]
{
        exec_dset("/usr/local/bin/selectserver.sh");
        if (!t_relay()) {
                sl_reply_error();
        };
}

selectserver.sh alters the server in the destination URI to choose from 
a dynamic pool of servers that's always changing according to a funky 
proprietary logic of ours. This works just peachy. The problem is 
OpenSER stays as man-in-the-middle all the time. I'd like it to do a 
REFER to a random server of our choosing and stay out of the loop from 
there on. How could I do that?