multihomed server on isolated networks

FreeRadius version 2.2.0 OS: RHEL 5.5 Hi Everyone, I have a requirement where a DHCP server should have a leg into a number of isolated networks. Which means that when I set DHCP-DHCP-Server-Identifier as an interface address only one network will find it. My current options include setting up routes on other networks to the respective interfaces, numbering the loopback and again doing the same, however I was hoping that there maybe a configuration option that will set the Server Identifier to be the IP address of the egress interface. Please let me know as to what is currently possible in my scenario. Regards, Lev Bronshtein