A solution is proposed for exchanging messages (such as e-mails) among a plurality of data processing entities, such as client computers (105). A corresponding method starts with the step of sending (403-412) an original message from a sender entity to a set of original receiver entities; the original message includes an original information content and an indication of the original receiver entities. The method continues by sending (415-424) a correction message from the sender entity at least partially to the original receiver entities and completely to a set of missing receiver entities being missing in the original message; the correction message includes the original information content and an indication of the original receiver entities and the missing receiver entities. The original message for each original receiver entity is then corrected (427-496) according to the correction message.