When setting up a collaborative venture, hospitals typically fail to significantly improve their overall performance due to lack of integration of clinical services and resource management. In this study, we develop a novel collaborative mechanism via empirical and computational research to facilitate negotiation between two hospital entities in search for a game-theoretic Nash equilibrium. This mechanism design enables a sustainable cooperation while social welfare is maximized. Such an automated approach not only increases efficient decision-making but is more effective in finding a stable agreement, considering individual objectives of involved parties. The mechanism design is based on development of new robust case-mix models to improve accuracy of decision-making, integrating strategic planning and operational resource scheduling decisions. In this latter regard, we consider most important types of hospital resources, i.e., main medical resources in the operating room department and beds in the downstream hospital units, enabling evaluation of (higher-level) policy decision-making based on operational performance and involved risk. The developed framework is inspired on empirical drivers of hospital collaborations and observed performance and is used to study benefits of hospital alliances with a varying degree of collaboration involving willingness to cooperate, range of partnered activities and centralization of activities.