Capture emails that don't have a mailbox and forward to my account

Capture emails that don't have a mailbox and forward to my account

Hi,

I want to capture all emails sent to our domain that don't have a corresponding mailbox. ie I have 3 email accounts that have mailboxes, i want everything else that it sent to our domain captured and sent on to my mailbox. How would I do this?

Many thanks for any help.

Regards
Craig