In a two-level decentralized system (a corporation) consisting of a headquarters and divisions, it is required to make its decision considering not only competitions with others but also the coexistence with the social environment to persuit the overall development of the corporation. This paper develops a "single-objective, two-level decentralized system" into a "multiobjective-headquarters, two-level decentralized system" and formulates a mathematical model for the extended system. A method for generating all the nondominated solutions is proposed by exploiting the properties of a set of feasible extreme points in the mathematical model. A numerical example is demonstrated to show the effectiveness of the proposed method.