This study develops a framework of integrating multi-objective decision support systems (MODSS), expert systems (ES) and group decision support systems (GDSS) effectively to deal with multi-objective decisionmaking problems in a group under knowledge-based intelligent guide. The three dimensions, MODSS, ES, GDSS, are combined to overcome the limitations of each basic system and maximally enhance the competence of the integrated system. As part of this study, this paper proposes a two-level multi-objective based group decision systems framework and five group aggregation methods. A group subsystem is then developed to include the five aggregation methods in a method base. This makes the exploration of group satisfactory solution more flexible and effective.