That paper tackles the issue of competence increase in networks of firms, taking advantage of collaborative relationships. By hypothesis we limit our approach to competence increase for individual firms within a network, and we don't cover the increase of collective competence of the network itself. We develop a framework of decision support system, which objective is to compare alternative plans of actions for the collaborative development of competencies. We use a multi-criteria decisional method, and we formalize the decision process based on five criteria including the evaluation of value creation, cost generation and equity between partners. We apply the approach to an industrial case study of SMEs, in the field of software development.