You can create groups with those names, except admin, which has a special user already. Perhaps you’d call it “medical admin” or similar. Then you’d create create categories for them for their discussions.
See How to set / configure private / closed group access, membership and visibility
Also see Setup DiscourseConnect - Official Single-Sign-On for Discourse (sso) for hints on how to set up sso and pass those group memberships on login.