A dynamic message engine allows the merging of data using a variety of databases to deliver mail items to selected recipients, wherein the mail items include content which is filtered or otherwise limited by the system. In one embodiment, invitations to seminars (e.g., seminars directed at pharmaceuticals) are prepared and sent to a plurality of physicians selected from a physician database, wherein the content of the invitation includes text selected from a predetermined set of acceptable text items and/or wherein the content is filtered in accordance with predetermined criteria.