Prevent Service Desk Notifications Sent to a Group - Using Email Channel

[A McCoy]

Hello,

I am trying to determine a way to prevent my users from adding a specific email address to service desk requests. We have an email channel set up with one of my service desks. The email address in question that we do not want to be added to requests has over 800 employees and when users are emailing the desk and adding the email address in the TO line of the email, the request is created and notifications are sent to 800 other employees.

I have attached images of my global setting, as well as the Customer Permissions setting for that specific service desk. I am wondering if there is anything I can change in these settings to prevent 800 people being notified?

Any help is so appreciated!