The integration of topological predicates on spatial objects into a formal constraint language is an important field of investigation. The present paper proposes an extension of the Object Constraint Language (OCL): Parametric-OCLCBM. P-OCLcbm integrates the Calculus-Based Method (CBM) into OCL and allows the definition of two parameters to express the numbers of parts of each of two composite regions involved in a topological relationship. Thus, it facilitates the specification of relationships between composite geometries, i.e. geometries made of several simple shapes. The expressive power of P-OCLCBM is studied from a spatial point of view.