Nowadays there are guidelines, frameworks, models and toolkits that support the devel-opment of multi-user interfaces. Toolkits assist designers in buiding the interface, whereas guidelines and frameworks direct the designer towards issues to be considered during interface design. Models, on their turn, allow for the description of the conceptual model of the group (or part of it) to be represented in the interface. Nevertheless, none of these provide the designer with an environment in which to plan and define the system`s interface. We take a Semiotic Engineering approach, in which the interface is perceived as a one-shot message being sent from the designer to the users. In particular, interfaces can be viewed as meta- communication artifacts, since they can also exchange messages with the users. Further-more, in multi-user environments, they are also communication embedding artifacts, since they allow for the communication among users. This approach focuses on the expression of the designer and requires the development of means to support this expression. In this work, we intend to provide support to multi-user interface designers, in a Semiotic Engineering framework. In order to meet our goal, we developed a meta-communication model from which models and techniques to support the development of multi-user interfaces can be developed. The meta-communication model proposes that designers should be provided not only with means to describe their messages, but also some qualitative indications on their description. Based on this model, we developed a model of an architecture to support the design of multi-user interfaces. This model assists designers that develop multi-user interfaces top-down. Therefore, this work is the first step in the direction of an environment to support the design of multi-user interfaces with quality.