The OpenHIE Interoperability Layer Community (OHIE-IOL) aims to enable easier interoperability between Health Information Systems. Key activities of this initial phase are to perform a critical review of the architecture and technologies used in the development of the RHEA implementation of these HIE components, as well as a comprehensive review of alternatives, to ensure due diligence.

See http://openhim.org  for more details of the OpenHIM application. 

The documentation is available at Interoperability Layer Community Documentation

There is also a  Github repository, which are intended as open collaborative work spaces for all interested parties to add to this work.