session & htaccess

Hi all,
/home/mydomaine/www/.
/alluser/authuser/files


dir alluser is free (accessed by http://mydomain.com
dir authuser as all php files resticted by a session (session_start...)
dir files MUST be accessed by an auth user (session started)



and the URL http://mydomain.com/alluser/authuser/files/myfile1.mf
should'nt work without a session was started

how can i do??

<?