Modern business activities rely on extensive email exchange. Various solutions attempt to analyze email exchange in order to prevent emails from being sent to the wrong recipients. However there are still no satisfying solutions; many email addressing mistakes are not detected and in many cases correct recipients are wrongly marked as potential addressing mistakes. In this paper we present a new approach for preventing emails addressing mistakes in organizations. The approach is based on analysis of emails exchange among members of the organization and the identification of groups based on common topics. Each member's topics are then used during the enforcement phase for detecting potential leakage. When a new email is composed and about to be sent, each email recipient is analyzed. A recipient is approved if the email's content belongs to at least one of the topics common to the sender and the recipient. We evaluated the new approach using the Enron Email dataset. Our evaluation results suggest that the new approach easily copes with email recipients that have no previous direct connection with the sender.