Execution of rlm code when remote server is not responding.

Hi, I have a remote PPS server where I am proxying radius requests coming from the NAS. I have a requirement like when that remote PPS goes down(which I am simulating by setting a wrong ip in proxy.conf realm configuration) then I have to perform a certain task in rlm code.But my observation is when I am setting a dummy ip for PPS, the radius server running on my machine is marking that remote server as zombie after 3 retries,now I want in this case that my rlm code to execute and handle the scenario when remote server is down.Any help will be highly appreciated.Also I may have used some naive terminology being a newbie apologizing for that. Regards, Arka