Seeking advices in how to create several accounts for a single vendor.

Hello,

I'm building an multi-vendor ecommerce website and I need some help with a request that I just got. By default, the website will create a single account per vendor. The request I got is to allow several accounts for a single vendor. For example:

Let's say the vendor ACME is a big retail shop and it wants to list their products on my website. Because of ACME's size, each department manager will be responsible for the products listing. That means the website will need to create an account for each department's manager. 

My question is how do I go from one account per vendor to multiple accounts per vendor? How would you design/change your DB scheme?

Regards,
Castle