Preventing use of third-party authenticators with Azure MFA

Question about preventing use of third-party authenticators for Azure AD MFA:

In Azure AD Authentication Methods, we currently have Third-party software OAUTH tokens limited to a specific group of users.  We also have Allow use of Microsoft Authenticator OTP turned ON in the Microsoft Authenticator configuration.  Finally, we are in 'migration complete' mode, with all of the legacy MFA settings disabled.  

When users who are not in the specific Third-party software OAUTH token group I mentioned above are prompted to set up MFA, there is a link to 'I want to use a different authenticator app', which they can choose and set up any third-party authenticator app.  Is there a setting I'm missing here to prevent use of third-party authenticators?