How to notify customers when an agent reply to their incident?

We have GoToAssist set up to create incidents when users send emails to a particular email address.  The incident will have the customer of the person that sent the email and the watchlist will include everyone that was on the email.

When we add comments and check the watchlist, an email is sent to the customer and all the users in the watchlist.  However if someone replies to that email, we only get an update in the incident.   We would like everyone to get the reply from the one user.  Is this possible to do?  Thanks.