I don't think so. The information of the user(s) who receive the blind copy is stored in a field called InetBlindCopyTo. The mail documents of the sender and the blind copy recipient both contain this field, but it is missing in the document of the user(s) that are listed in the fields 'To' and 'cc'. In your example: The memo documents from users A and B contain the field, but it is removed from C.