As far as I know laravel configuration files must return an array which will be used in configuration. There can be some logic code in there which produces wanted configuration.
Instead of following usual pattern:
<?php
return array(
'media' => '/media/',
'media_users' => '/media/users',
};
You can do this instead:
<?php
$mediaDir = '/media/';
return array(
'media' => $mediaDir,
'media_users' => $mediaDir.'users',
);