Online Store Store

Every time I can't find a product on the website of a specific store, I have to call the store. It would be great if there was a website where you could put in the name of the product and the location of the store and the website would tell you whether or not the product was in stock and at which store. <br><br>I know stores have this information available, because you can call the store and they can say whether or not they have the product you're looking for.<br><br>That's it. That's my idea. Is it possible? Does it already exist?