Equivalent of Packet-Src-IP-Address for DHCP

Hi Everyone I have a DHCP server which listens on multiple interfaces and would like to run the requests thought different bits of unlang depending on the incoming interface. Could anyone advise whether there is a way to get this info from an attributes like we do in RADIUS (e.g Packet-Src-IP-Address). I guess one way to do this would be to configure separate virtual servers, but I just wondered if there was any way to do it using attributes. Thanks Ben