The script can be used to disallow adding groups to other groups. When executed in a business rule triggered Before adding a member to a group, it will cancel the operation if the new member is a group.
PowerShell
$member = $Context.BindToObjectByDN("%member%")
if ($member.Class -ieq "group")
{
$Context.Cancel("You cannot add groups to other groups!") # TODO: modify me
}