This work develops a cooperative content caching framework for Social Wireless Networks (SWNETs) in which content demands are hierarchically heterogeneous. The heterogeneous request model incorporates user preference for different categories/genres, and contents under each category, both following power law distributions at local as well as global levels. Based upon such request generation model, an optimal Heterogeneous Split Caching (HSC) algorithm is proposed which can minimize electronic content provisioning cost using cooperative caching policies. Detailed simulation experiments for functional validation and performance evaluation with respect to traditional caching strategies are then performed under various protocol and network parameters. The baseline HSC mechanism is also tested against a special benchmark situation that provides a steady state performance bound, which can occur after an infinite request horizon.