IMAP / Email Sync Exclusion List

The IMAP email sync feature will collect email to and from any email address in Contacts or any custom objects I set up. This is usually fine, but sometimes we have email addresses that we don't want to sync for privacy or other reasons. We would like an "email exclusion list" so that specific email addresses are never synchronized.

Here are two recent examples needing this feature:

• Users in a Custom Object - we created a custom object named "Users" for all of our Ontraport users, and email to them. However, this is my staff and I don't want any of their emails synchronized into their custom object record in Ontraport (things like HR issues, private email about disciplinary actions, etc.)
• Our attorney is a contact in Ontraport. We don't want to sync privileged emails from our attorney into Contacts where any user can view them.  We also store other business contacts in Ontraport and have the same issue for them. 

Being able to add individual email addresses to an exclusion list for IMAP email sync would be a great addition!