You can put this into the Where condition in a query for a simple solution. For example in AdventureWorks this:

SELECT

NON EMPTY [Measures].[Reseller Sales Amount] ON 0,

[Geography].[State-Province].[State-Province] ON 1

FROM

[Adventure Works]

WHERE

{[Geography].[Geography].[State-Province].&[NY]&[US],

[Geography].[Geography].[State-Province].&[SD]&[US]}

...would give you reseller sales in New York or South Dakota.