Owing to the great degree of mass integration and energy integration: between the prefractionator and the main distillation column, it is usually infeasible to achieve a four-point composition control policy (i.e., the control of the main compositions Of the three products and the ratio of the two impurities in the intermediate product) in a dividing wall distillation column (DWDC), and this restricts, to a certain extent, process applicability and flexibility. The issue is referred to as the black hole problem in the current work and has received very little attention so far In this paper, an attempt is made to tackle this intricate problem, and the number of stages in each section of the DWDC is used as adjustment variables to coordinate the relationship between the prefractionator and the main distillation column involved, A simple and yet effective procedure is devised to guide the structural modifications of a given DWDC and the separation of two ternary mixtures of hypothetical components, A, B, and C, and benzene, toluene, and o-xylene are chosen as illustrative examples to evaluate its feasibility and effectiveness. Through steady-state analysis and dosed loop operation studies, it is demonstrated that the black hole problem can be completely circumvented with the careful adjustment of the number of stages in each section of the DWDC. This outcome gives evidence to the feasibility and effectiveness of the proposed philosophy and :indicates a reasonable way to enhance the applicability and flexibilities of the DWDC.