usability - Is the term second degree customer/user/client acceptable or easy to understand? What is a better alternative?

I am trying to describe a situation in which you design a product for a company, and they use it to engage with their customers. So from my own perspective, the company would be the primary (or first degree) customer, and the company's customers (or second degree) customer can be unambiguously described. And if the company provides a service to another company that also deals with their own customers then you can call it a third degree customer (and so on and so forth). Has anyone come across this term, and is it easy enough to understand or do people use other terminologies?

Often these days people talk about a B2B versus a B2C software/application. In this case a B2B software is designed for a business that have customers, and you would refer to the company as your client/customer and that company's customer as their clients/customers but it seems a little awkward to use this term.