Mobility allows social communities to become a ubiquitous part of our daily lives. However, as users in such communities share huge amounts of personal data and contents, new challenges emerge with regard to privacy and trust. In this paper we motivate the necessity of advanced privacy enhancing concepts, especially for mobile communities and outline the approach of the PICOS project in order to elaborate such concepts. We explicate how we collected mobile community requirements and elaborated adequate concepts to address them. Finally, we conclude with details on how the concepts were prototypically implemented to demonstrate their feasibility, what distinguishes them from existing work, and how we intend to transfer the concepts to practice.