include path-problem

Hi I have a problem with the include command.I want to include a txt file in a php file.But this txt file must include in every php file on the server and these phpfiles are in different directories. Here is the Problem : www.domain.com/index2.php and www.domain.com/support/shop.php must include the txt file from www.domain.com/includes/news.txt. So i used for this problem <?php include("/server/path/includes/news.txt"); ?> for every php file.But this works only for the www.domain.com/index2.php file. So what should i do to get the txt file in the www.domain.com/support/shop.php file ? Thank you very much for support !!! chris