The Purchase Order List includes the column header Currency. As with all column headers selecting it will activate ascending/descending sort. Alternatively, it can be dragged into the group field as shown below to view the list by Currency.

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You will see some letters underlined in the field names within the header, eg. Vend#. Using Alt+ the underlined letter will jump you to the field beside that heading. |
Purchase List Advanced (tab at bottom left of screen) includes the option to refine list results by selected currency.

Further information: