Radius relay the request to another one if there is an access-reject

Hi all! I need to set up something and I would like your opinion on how to do it. Freeradius (v2.1.8) asks kerberos/ldap to authenticate and authorize. What I want to do is if a Radius doesn't find anything (meaning access-reject) then it asks another Radius located at another host. Therefore Radius would relay the request. I started looking into this and I think I could do this somehow by configuring Radius as a proxy. Do you agree if this is the correct way to do? Feel free to let me know if you have some inputs which could help me. Regards, Gregory.