Emily, when I click "Create Invoice" on a Sales Order, I am given the option to "Create and View Invoice", at that point, I can click "Edit" in the top left. I can then change "Account" in the top right to any Account Receivable. Does this answer your question?

Re: Automatic:

I believe you could create a custom module that checks a custom field on the sales order for "China", but then you would still have to select "China" on every sales order, so it is not necessarily automatic.

You could do it based on the Customer, is that what you are looking to do? (Customer>Accounting>Account Receivable)

If you provide more details of how you are using it and what you are trying to do, that may help.

Thanks!

But I would like to have some automatically method instead of changing it manually every time.