From Roaring Penguin
To implementat multiple email address for the notification:
- In the webui navigate go to the stream where you are interested in making the setting.
- Go to Preferences->Notification page.
- Under the Basic Setings heading for the item "E-mail address for notification of pending messages:" for the Value you enter a comma-separated list of addresses.
Remember this setting takes effect only for the stream in which you make the change.