Best way to check for user 'Administrator' group membership

Hi all, System: Windows Advanced Server 2000 running IIS5 PHP version 4.3.3 running CGI User authentication: via Windows (all users) Question. I have a web site I put together that is used by many different users. These users are all local accounts. Some are members of the Administrators group and others are just general users. What I want is a way to determine is the user is part of the Administrators group. If so the user will see an extra menu option. If not the option will not even be available to them. I was trying to accomplish this via a local file site to be accessible only by 'Administrators'. I added the PHP function 'is_writable(<filename>)' to my code. This does not seem to work. Any suggestions? FPM