Copy Directory recursively from one project to another (API)

I have a repo in a project called curriculum. What I want to do is use the api v4 to create a new project with a repo that is made up of one of the subdirectories of the curriculum repo. I think I can do that with the repository files api, but that adds a commit for every single file. For example, I have a project with the repo: topic/lesson1/exercises. I want to pull the exercises directory, all files and subdirectories, and make a new project with a repo: exercises. We are self-hosted on 14.4.1 CE. Thanks!