Leaving aside the legal and logistical problems associated with your plan best of luck getting the company bean counters to pay to set up that kind of service.
I could even see that in the case of large airline groups. In fact i do use the services of the Lufthansa medical center myself, but expecting any AOC holder to have that kind of infrastructure? Not a chance in hell. And it still wouldn't prevent anything critical. And it wouldn't work, at least in germany, without large changes to several laws. For example has everyone the free choice of MD as long as the MD fulfills a few basic requirements. Especially the employer cannot force any employee to go to a certain MD or AME. Not to mention the privacy law which is not going to change.