FEU/CustomContent text on failed login attempt

[skypanther]

Can I output custom text after someone tries to log on and fails? Ultimately, I'd like to output either a "bad username/password" message or a "you don't have sufficient rights" message, depending on why the log on failed. As an example of the latter, let's say I have a page that requires you to be in groupB but you're in groupA.

Thanks,
Tim