restrict access to page to only be allowed from a certain page

[eleetproof]

This question is similar to the one i asked http://stackoverflow.com/questions/2015398/is-it-possible-to-tamper-post-data-when-using-frames then they cannot get to http://intranet/other_page.html without using the link provided in index.html. Is this possible and if so what would the best technique be? I'm using apache to serve the site and I have php and javascript available.