Thanks for your post Gary! You're correct that announcements come from a no-reply email address. In order to count toward the "engaged" metric they would need to click on the action button in the campaign. 

Keep in mind you can create a hyperlink to email in the body of your campaign as well. It won't be tracked in your metrics, and may not capture all of the information you require by having them interact through the portal, but will enable the customer to email you