Multiple shared secret per IP?

On FreeRadius v.3.0.12.  I have a requirement where I need to send test authentications to the F.R. server, which are then proxy’ed. i.e: user: monitor source IP: 64.0.0.1 secret: MonitorAgent ^ - That’s easy. To complicate, I need to also authenticate real users from the same source server, using a different shared secret.  (anyone can view the one above, so not secure) Ideally, I’d like to also lockdown the above secret key, to the single user. i.e: user: userA, etc, etc source IP: 64.0.0.1 secret: SD%^GHJ Is it possible to have multiple secret strings per IP or maybe different domains per IP?  If not, any recommendations? Thanks!!