Hiding Bcc from SentItems

My company’s employees are not keeping our manager in Cc when communicating with director/ CEO level person. So I want to keep my manager in Bcc in all outgoing mails. That I can do creating a macro in Outlook. But I don’t want the sender to know that my manager is in Bcc. Currently they can see it just by opening that mail from SentItems. So is there any way to automatically hide Bcc in such cases from SentItems ?