AWS API Gateway: Create one API for both public access and private access

Question

I would like to achieve these below. What are good ways?

• Make one API on API Gateway. (I prefer one API over two APIs to save maintenance cost.)
• The API can be accessed from the internet.
• The API can be accessed from the VPC without data transfer out charges. (https://aws.amazon.com/api-gateway/pricing/ "There are no data transfer out charges for Private APIs.")

Problems I face to

• In API Gateway settings, I can choose either "Regional" or "Private" (never both).

Expected structure