Linking Multiple Vendors to one app

You need to imagine how many levels you need.

As a guidance to discuss, take a look at this

For restaurant’s terms,
lower could be your food & beverage order items, middle is your bills to customers, higher is your restaurant’s branch, highest is your restaurant’s business.

You can add more layers as you like, but complexity will follow.

Design the entity relationship diagram first, then create collections with its relationship property, then you can begin adding screens and logics.