Borrowing service in-app

We are building an app that users with library cards would be able to have access our content of ebooks and audio books to borrow for a limited time. The users with these registered library card numbers sign in ( would not get charged by us ) search within the list of contents select the book and borrow it, book will be delivered and downloaded in their in app library After the borrowed expiry date, the content will be removed from their library. I am not sure if it's considered B2B2C or not as there's no transaction in-app.

Is there a document that I can read on Apple T&Cs for this business model?