I do this by adding users to a group for the notification (in my scenario I can reuse the group for other purposes as well, so it is fine) and then use acs-mail-lite (new version from HEAD) which allows you to pass in a "to_group_id". Then make it send immediately and the emails are being send out via SMTP where the mailserver takes the "hit" so to speak. And as they are all individual e-mails it still works.