E&M and diagnostics are not mutually exxclusive, and don't hit a CCI edit.
Here's the question: are the hospital's radiologists also reading these Xrays, or do your providers have a contract with the hospital to exclusively do so? If their radiologists are reading the xrays, and they're billing for both the professional and technical component on the UB, then your docs cannot also bill for the read. The read is going to require a report go into the hospital's medical record, so if your docs are billing the read with the -26 for their own purposes alone, you are unbundling and are not entitled to that payment. Just becasue you read an xray doesn't mean you can bill for it. you can include that read as a data point for calculating medical decsision making for your MDM.
If you do have a contract to be the reading provider for those imaging services, then this sounds like a payer edit.