may/can

hi, i would like to know if the following sentences are correct and what is more formal/polite "can" or "may", in the sentences:

Well, it is a well known fact that the health care professionals I’m talking about can/may specialize in certain disease types, patients, or types of treatment as specialist physicians or practitioners; in alternative they can/may focus on broad and comprehensive care for individuals, families, and communities in which case they are called general practitioners, a synonym for family doctors.Who usually work in private practice as individuals, teams, or groups; as well as in hospitals and clinics. While Most specialist physicians work at hospitals.
~~~
Well, it is a well-known fact that the health care professionals I’m talking about can/may (can means able to and may means allowed to) specialize in certain disease types, patients, or types of treatment as specialist physicians or practitioners. Alternatively, they can/may focus on broad and comprehensive care for individuals, families, and communities in which case they are called general practitioners, a synonym for family doctors. Family doctors usually work in private practice as individuals, teams, or groups; as well as in hospitals and clinics, while most specialist physicians work at hospitals.