Representing a graph of person relationships beyond those that pertain directly to patient care (either representing an actor involved in care, or family history of illness) is really outside the scope of FHIR. There are several security and privacy related considerations (e.g. GDPR) to representing a full network of person relationships in a healthcare system. In some cases, it might be appropriate to use Patient, if the related person is a Patient, however not all personal relationships are appropriate to represent in Patient (e.g. a great-grandmother that never received care at the relevant organization). You might consider using extensions on Person to document the relationships that person has with other persons.   We do think we should clarify the Person resource narrative to clarify that the "networks" that a person may be involved in are networks for the purpose of healthcare provision, not networks of personal relationships. Proposed update to the Person Master Index section on the Person resource: These may also operate outside of government in the private sector, such as associations or healthcare networks that a person may be involved with and may work in the same was as they do inside government. The usage of the data into the healthcare environment is not the only use of the register.