First of all, each hospital should have an agreement of interoperability between them implemented by the hospital director, like MOU. Then, the patients in the area should know for personal benefit. The representation of healthcare providers and public health officers of every hospital makes an agreement of what data should be linked. Then, informaticians who act like an EA will work with a programmer, database administration, or security specialist, for instance, to planning a blueprint of the system and think about how to link the data among the different systems.
After the first draft is released, they all should work together again to evaluate and revise the plan.