How to associate Appointment resource to a CareTeam/Group resource in FHIR R4? It has no issue for R5 (http://hl7.org/fhir/R5/appointment.html#resource) as Appointment.participant.actor can has reference to CareTeam/Group, however not for R4 (http://hl7.org/fhir/R4/appointment.html#resource). How to achieve the same as R5 without upgrade FHIR version (which I have no permission to upgrade)?
You can use the inter-version extension mechanism to pre-adopt the additional data types from R5 in R4.