Limit FTP access to IIS 4

Hello.

We are using an FTP server (IIS 4).

Is it possible to grant FTP access only to specific groups of users?

A friend of mine told me that this is possible in IIS 5 but what about IIS 4?

Our problem is that we do not want some of our domain users to be able to have FTP access from outside.

Thank you in advance.