Authorization on IIS5 (PHP4; Win2k)

Hi, I'm trying to set up user-specific site settings with authentication. I need to be able to validate accounts to a Win2K Active Directory server, as there are several hundred accounts active, and they change on a regular basis. I have the IIS authentication working fine, but I want to be able to have a way of checking their group membership (in Win2K) so that PHP can determine whether to display certain pages depending on whether they are members of administrator, student or teachers groups. I am pretty sure that there is an IIS interface for ASP (VBScript) to get the username/password variables from the IIS Authentication, but I don't know how or if it is possible to access that using PHP's COM support. I can do this manually in PHP, but like I said there are too many accounts to handle this way. I think that I can use cookies to store the user preferences, but am I right in thinking that if they log on from another computer their settings won't be loaded? At this point I am considering handling the initial login information gathering through ASP and then passing that information to the PHP pages. Any and all help on this is much appreciated. Joel Gilbert MCSE