Setting a default Ship To address for local pickup orders

Hi, I'm wondering how I could set a default "Ship To" address (this would be the address of our physical shop) for local pickup orders. The use case scenario would be:

1. A customer places an order on our Squarespace store for local pickup.
2. A default "Ship To" address would be populated with our physical shop's address
3. With a default Ship To address, local pickup orders would be exported/synced to Shipstation

Does anyone know how this would be done? It would be greatly appreciated that way we can continue to do all of our order fulfillment through Shipstation without our employees needing to have logins to both Shipstation and Squarespace. We would setup an automation rule in Shipstation to tag all local pickup orders (those with our shop's address as the "ship to" address) so that we can fulfill the orders separately and have them ready for pick up instead of purchasing a shipping label.