Question: Limit ordering ability based on location

I have a bit of a unique use case, I suspect, but it may be something that the plugin can already do (or something you think useful enough to add).

Use Case:
I am creating a store for a client who sells trees to landscape architects. Because of the nature of what he sells, it doesn’t make sense for a client to order from both of his farms in a single order. So I want to allow clients to order only from a single farm.

Features that would support this (which may already be in there):

1. Add a widget to allow customer to search only one farm. Ideally, this would persist through an entire session so a client would be able to only shop a single farm if he knows which one he wants.
2. Prevent customer from adding item to cart that exists only on other farm. Seems to me, I could replace the “Add to cart” button with something letting them know they can’t order from both farms at the same time or throw an alert/error when they do.
3. Maybe: Once an item is added that exists only on one of his two farms, automatically filter viewable items.
4. Display (not allow selection since I know you said you don’t have that capability in there, yet) farm locations on the product page

I’m sure there are other details, but that’s what comes to mind. Honestly, if #2 could be achieved, I could deal with the rest. Numbers 1 and 2 would fully solve this with the other two being nice enhancements.

Thoughts?

Thanks,
Joe