In the notification configuration screen, it allows to set email destination for each different message.
If you need to send to more than one destination, you can configure two or more email messages. then sending them when needed.
It is better not send more than 3 emails at once, because we had shrunken email queue size to 3. More emails sent at once will push out the earlier email, if that has not been sent.
If your firmware is an older once, it may only has one email address to be configured. In that case, you can send the board in for firmware updates, so that you can configure up to 8 email addresses.