[GENERAL] Allow login on slave only

We run a master server and a hot standby server. Reporting users login to the standby server to run long queries. However, their login is also valid on the master server. Is it possible to prevent a user from logging in to the master server?

A statement like:

    alter role newbie_business_analyst nologin;

Is replicated, so it would block logins on both servers.

Thanks,

Andomar