if (in_array('is_admin', $user_groups)) { // allow access to admin-only features } else { // restrict access }This code checks whether the user belongs to the is_admin group or not. If they do, they are granted access to the admin-only features. Otherwise, access is restricted. The package library for this functionality could be any PHP framework or library that supports user authentication and authorization, such as Laravel, CodeIgniter, or Symfony.