This question has been answered by BobRay. See the first response.
$group = 'SomeUserGroup';
$role = 'Editor';
if (!$user->isMember($group)) {
$user->joinGroup($group, $role);
}$user->joinGroup($group);
if (! isset($_SESSION['new_user'])) {
return '';
} else {
unset($_SESSION['new_user']);
}
$group = 'SomeUserGroup';
$role = 'Editor';
if (!$user->isMember($group)) {
$user->joinGroup($group, $role);
}