How can one warehouse be used to deliver goods to different countries?

Hello community!

I have a Shopify store where I want to sell products in the USA, Canada and Australia.

The goods will be physically located in a warehouse in the United States and will be sent to all countries from there.

Therefore, the quantity of available goods for all three countries will be the same. How to set it up correctly?

If I create a single location - USA, then in this case it is impossible to order the product if the client specifies the delivery address of Canada or Australia

if I create a location for each country of delivery, then I have to write the availability for each warehouse separately (although there is actually one warehouse and all goods in this warehouse are equally available for any country)

Please tell me how to set up the sale from one warehouse to different countries from one store, while the warehouse and the quantity of goods were common to all country.

Thank you!