Previous research in Group Support Systems does not include a design theory for GSS-enabled meetings. As a consequence, problems are experienced in the design, implementation and evaluation of GSS-enabled meetings, particularly in difficult cases where the issues have a history of confusion, conflict and the exercise of power. This research proposes a design theory in the form of an inquiring system based on some aspects of the work of the late C. West Churchman and the German idealist philosopher J?rgen Habermas. The application of the design theory is explored via empirical data gathered in the premeeting, meeting, and post-meeting phases of a GSSenabled intervention in the domain of strategic urban planning. The focus question is "Do an inquiry-based design theory and electronic discourses reduce participant conflict and confusion about a comprehensive urban plan and preferences for three scenario options?"