The secondary email can only receive email through the Carbon Copy Option. This can be set during the Delivery Setup process of sending an email.

When setting up a message for delivery:
  • Click Select Delivery Options under Related Actions
  • Click CC all recipient email addresses under the Carbon Copy Option
If a constituent is in your target group and they have a secondary email address on their constituent record, they will be sent the email at their primary email address and CC'd to their secondary email address.