I am looking to find a solution to a situation I have.

I send emails to over 1,000 contacts for a website I work on. Every once in a while a contact may no longer be a valid contact (change of contact person) and I want to prevent sending them an email in the future.

Is there a block list for outgoing mails? I want to prevent looking up old contact information or email string and email somene who is no longer my contact to avoid bothering them.