We present a new discrete model to identify the most stable networks in polyhedral water clusters. The model relies on the screening of the energy of the local network based on the concept of 'strong'/`weak' nearest neighbor interactions according to their (trans/cis) orientation and the connectivity of the respective pairs to neighbors. We apply this model to the pentagonal dodecahedron (H2O)(20) cluster using a hierarchical description of the intermolecular interactions using classical interaction potentials and several levels of electronic structure methods. This study offers a practical and efficient approach for identifying stable networks in clathrate hydrate structures. Published by Elsevier B.V.