Collaborating entities usually require the exchange of personal information for the achievement of a common goal, including enabling business transactions and the provisioning of critical services. A key issue affecting these interactions is the lack of control on how data is going to be used and processed by the entities that share it. To partially solve the issue, parties may have defined a set of data sharing policies regulating the exchange of data they own, or over which they have jurisdiction. However, distinct set of policies, defined by different authorities, may lead to conflicts once enacted, since, e.g., different subjects may have defined different permissions on the same data set. This paper focuses on policy analysis and offers a formal support for coming up with a conflict-free set of data sharing policies. We illustrate the methodology on the example of an emergency management.