We are building a Shopify Plus store with 2 locations - east coast and west coast. The 2 locations have different inventory levels for each product. We are able to "assign" a location to the customer based on their shipping address, BUT -- Shopify will automatically fulfill the order from any location if there isn't enough available at his nearest location.
For example, if the customer is east coast, and he orders 5 of a product and there is only 3 available in the east coast location, it will take 2 from the west coast location and fulfill the order. We are trying to find a way to stop this from happening... whether that's an existing app, custom app / API, checkout scripts -- anything. Having 2 separate stores for each location is not a solution for us.