An organization usually operates its own mailing system to provide each person with an e-mail address under its domain name. There may exist a number of mailing lists in use, each of which refers to a group of its subscribers. The problem entailed in this conventional mailing scheme is that it requires constant administration from its initiation to its maintenance. This paper proposes a rule-based mailing system where e-mail is delivered based on rules, instead of its recipients' e-mail addresses. With this rule-based mailing approach, the administrator need not any more manage individual e-mail addresses and mailing lists respectively since it guarantees a single point of administration by involving the organization's database. Furthermore, it virtually offers numerous mailing lists without actually having them. Our rule-based mailing scheme is straightforward to establish, fully compatible with any existing mailing systems, yet achieves an efficient way to construct an organization's internal mailing system.