Look up EpicCare Everywhere. It interoperates with other Epic and non-Epic EHR systems.
I have it on good authority (the CEO of a hospital that uses Epic) that all versions of EPIC are different and unless you have the same version they don’t talk to each other.
Perhaps EpicCare Everywhere is a workaround solution to that. One would think that a hospital or medical care facility shouldn’t have to operate two different packages for EMR in order to function though.