you can create another group and add the www-data (if your webserver runs under www-data user) to this group, then assign this group to all those files you want to be accessed.
or if you just need the read permission, and it is not an issue that other users on the system have read access to your files, then just change permissions of your files (in other places) to have the read permission for other. fore xample 775 for your directories and 644 for your files.
remember that you can not serve pages in places other than your Document Root (for example /var/www), even though your webserver user has the permissions to access those files.
However if you configure "aliases" or "virtual hosts" for your web server, you can make
places other that your default document root, accessible by HTTP requests.
but PHP files that are under your document root and executed by the web server, CAN read contents of files outside the document root IF the web server user has enough permissions.
// file permissoins
/tmp/shared_by_all.txt -> 644
/home/user1 -> 751 or 755
/home/user1/shared_by_all.txt -> 644
/home/secureuser -> 750
/home/secureuser/myfile.txt -> 640 (or even 644 because of the containing directory permissions, other can not even enter the directory tree. so file is not accessible)
// file: /var/www/read_file.php
<?php
echo file_get_contents('/tmp/shared_by_all.txt'); // ok!
echo file_get_contents('/home/user1/shared_by_all.txt'); // ok!;
echo file_get_contents('/home/secureuser/myfile.txt'); // fail!;
?>