FHIR data in existing Nationwide Health Information Exchange

In the USA and elsewhere, there are Document Sharing based Health Information Exchanges. These exchanges have been built up over the past ten or so years. They have security models, privacy models, patient identification models, record location models, and data format models.  They also have mature testing tools, events, and have been specialized for many projects.The solution is to leverage this existing solution, and just add FHIR. The exchanges in the USA include a PUSH model as well as a Query...