Amigopod 3.7 is EOL, you really should upgrade to 3.9 if you still want support on Amigopod.
Multiple RADIUS proxy servers in Amigopod is not a recommended configuration.
RADIUS proxy cannot distinguish between "access reject because password is wrong" vs. "access reject because user is not found". Both of these have the same response - Access-Reject - but in the first case, you need to fail immediately, and in the second case you would typically want to fail-through to the next server.
With 2 proxy servers configured the only mode of operation available is backup: if the first server is unavailable, the second server will be used. There's no way to configure it differently.