Small Commercial Property, what will it take to get into one

Been reading this forum and there are a lot of great information on investing and how to buy properties that can returned a nice monthly income. Most of the discussions that I have read here been related to single family homes, duplex, tri-plex and 4-plex. Which is a great starting point for investors starting out and getting their feet wet.

Does anyone here have any experience in commercial properties (ex: commercial building with 2 to 3 business clients). I am not talking about something huge here, but maybe a small building by local hospitals. Where you see a lot of doctors owning their own private practices.

Just wondering what it would take to get into these buildings? Kind of the same requirements as a 4-plex? What kind of return can be expected from each door/client.