hiding folders in FTP

We're having an issue with the built-in FTP server for Tiger. We want to give our customers an FTP login and allow them only to their allowed sharepoints. The problem we're having is that we don't want folders for other customers to be listed. Permissions aren't letting people into folders they shouldn't, but we don't even want them listed if the user does not have permission to view the contents. how can we turn that off? We've tried doing home directory only but we still get sharepoints, so I dont know what the deal is.