David,
The EMPI sounds like the technology they use to address is Peter Parker also Pete Parker. That kind of work takes lots of iterations and is expensive to craft, so if you get that in the mix, that is potentially a good thing.
Taking a quick look at their website,
http://www.orionhealth.com/products/ it appears that they have a whole infrastructure for mapping and connecting different systems. They mention HL7 as well as CCD support, so my guess is that they can do XML parsing, which would be good for an AC integration.
The real question is what you want/need from the HIE - if I know that I can even reach out to these folks to translate.
