<?php
$key = array_search('custom|mode', $config->admin->menuGroup['system']);
unset($config->admin->menuGroup['system'][$key]);

$config->admin->menuGroup['feature'][] = 'custom|storygrade';
$config->admin->menuGroup['feature'][] = 'custom|epicgrade';
$config->admin->menuGroup['feature'][] = 'custom|requirementgrade';