76407 Access denial unless... script

I need a javascript, or PHP/cgi script that denies access unless the viewer is coming from a specific page/directory. I already have a pasword protected folder, however I need to give members access to pages found on an uprotected directory. But I also don't want those pages to be viewed by non-members. So I need a script that I can isert on any page and thus preventing the view of that page unless the person is coming from one (any) of /members directory.