Need info about Clients configuration.

Hi Am setting up radius server where I want to store the client addresses in oracle database. My setup would have about 1500 RADIUS clients talking to the RADIUS server and these clients would be dynamically added/removed And for some clients I may have to proxy the authentication requests. Hence I want to know is there a way I can specify a "default" client in the "nas" table so that the proxying can be handled easily?? Thanks in advance. -Vishwa.