Online social networks have gained enormous popularity in the last decade. Users share their private information online with other users, which is becoming a serious privacy issue at the social and technical level. In a society, everyone is a member of many collaborative groups (social circles), for example, colleagues, class fellows. There are many collaborative relationships among group members. Current social networks mostly use friend as a relationship, which in our social life, is not practical. In a society, we have different levels of collaborative relationships with others and even some relationship with non-friends. We use collaborative groups and relationships that facilitate users in controlling the privacy and sharing level of their information in social networks. We present a sharing and privacy-aware SP-RBAC model by extending the well-known RBAC model. Our model increases the collaborative community of a user, and hence increases sharing of information, minimizing the privacy threats using simple user management.