Sell Multiple (Wholesale) Licenses of the Same eBook

Hello! We sell a wholesale book (B2B), and our clients give the book to their customers.

Everyone wants an eBook version. What would be the best way to do this? We've tried many options.

Basically, it would be a client buying multiple copies of the same eBook, and being able to give one copy to each of their customers.

Thank you for any advice!