Well, if you want to do this, you need to know how to remove certain if conditionals:
PHP Code:
if (in_array(THIS_SCRIPT, array('register')))
{}
else
{
if (is_member_of($vbulletin->userinfo, 1)){
And add usergroups you want to see. So, you completely remove check for THIS_SCRIPT, and add all usergroups you want to see this notice, or, if you want really all to see, remove this if conditional altogether. Of course, you need to respect all curly braces (all open ones need to be closed after your editing).