This can be done by setup currency for Supplier.
The moment you pickup supplier on PO, it appears with default currency.
Thanks for the reply but that's not what I mean. What I'm looking for is to default to the purchase order with a set purchase price in a currency other than the base currency. So for example, if the base currency on the Org is GBP and the value of the List price on the Item master is 9.00 GBP, but this supplier is purchased in USD, with a purchase price of $11.75 USD, when the item is added to a PO in USD currency, it would default the $11.75 USD Purchase Price and not convert the 9.00 GBP to USD. I thought this could be done with advanced pricing, followed the Vision Demo, but it didn't work!