Ask HN: HL7 Integration Experts

I am trying to find someone that will help me validate some assumptions about a Health Care Provider integration project I am working on.

I am looking for someone that can help me understand what it takes to integrate in to a Health Care providers prior authorization work flow. We would be working with companies such as United Health Care and want to make it as easy as possible for them to communicate with our system each time they approve a prior authorization request. Right now we are thinking this would be done with some kind of HL7 Message to our system from theirs but do not have experience with HL7 or this type of integration.

Does anyone know of anybody that can help?