[Serusers] How to avoid calling route() in a failure_route block?

[Tim Klein]

I have an unusual need:  If a contact in the usrloc database is
unreachable for any reason, I must immediately delete it from the usrloc
database.  I know how to do the deletion, but I don't know the right way
to write my configuration script.

Below is the script that I want to write.  But I think it won't work,
because I think it's illegal for a failure_route block to call a route()
command.  (Am I correct about that?)

Can anyone tell me what I should do instead of the following?

Thank you in advance!

Tim

==============

route {

     [...irrelevant stuff omitted...]

	if (method==INVITE) {
		route(1);
	}
}

route[1] {
     if (lookup("location")) {
         t_on_failure("99");
         t_relay();
     } else {
         t_reply("404","Not Found");
     }
}

failure_route[99] {
	delete_location_from_usrloc();   # I will write this function.
	route(1);
}

==============