Social Media Graphic Library - Selling multiple licenses.

Hi. We would like to create a social media graphic library that I can make available to any client that registers for our service. The idea is we create the graphic once but offer it to multiple clients. I understand that this means each graphic must be licensed once for each client. My question is, is there an easy way to purchase additional licenses for these images contained in the graphics in bulk. We will likely have a library with hundreds (eventually thousands).  

Has anyone done something like this before?

This is just one example of a social graphic we might create. We purchase the stock photos and then "design" on top of the photo for the social post.