Aqueous polynuclear systems have been analyzed, for which the family of formation curves intersects at a common point. The analyzed graphical and computational method for determining the stability constants can be used as initial values within the iterative calculation process. In some cases, the stability constants are calculated using only the coordinates of the common intersection point. The obtained equations could be of special interest when the experimental data can be interpreted in several models. In these cases, given the large volume of experimental data, the calculation is simple and the model can certainly be chosen with a great safety. The obtained equations may also be applied for critical evaluation of tabular data, if the coordinates of the intersection point are known. A series of real polynuclear systems have been analyzed and useful conclusions have been made.