How to use Sales Office to Handle Different Currencies in different Sales Order for the Customers in China?

Hi

We have the customers located in China and when dealing with different sources to obtain the material, this china customer is requried to pay in different currency.

e.g.

1. Shanghai sells to china customer in RMB

2. Nanchang sells to china customer in USD

Other than defining 2 Sales Orgs each for Shanghai and Nanchang with RMB and USD respectively, I would like to go for single Sales Org in China and thinking to use Sales Office to achieve the above purpose - handling different currency due to different sales office values (Shanghai, Nanchang)set in customer master.

And this currency need to be defaulted in Sales Order during the creation of Sales Order.

Please advise.

Thanks.