ABE filters shared folders visible to a user based on that individual user's access rights, preventing the display of folders or other shared resources that the user does not have rights to access. ABE can be accessed via graphical user interface (GUI), command-line executable tool, and a robust advanced programming interface (API).

Documentation: http://www.microsoft.com/windowsserver2003/techinfo/overview/abe.mspx
Download: http://www.microsoft.com/downloads/details.aspx?FamilyId=04A563D9-78D9-4342-A485-B030AC442084&displaylang=en

Well, that remembers me at an other directory/filesystem called N... - well can't remeber that name! ;-)

Urs