restricting access to files using PHP

Hi, i've written a secure PHP login script which will allow users to login to a directory such as this: smezone.com/members/index.php however, how do I restrict people from accessing HTML files in that directory (which they can easily do so by typing the URL into their browser), such as: smezone.com/members/document1.html ? Since its a regular HTML files (and we have lots), I can't check whether the user has a valid session as I would do in a PHP file. Thanks for any help! Shams