Distinct count on several dimension members

Here is an example on how you can select the distinct count on a combination of product categories.
The example is written for FoodMart 2000

WITH   

SET [Categories] AS ' 
	{[Product].[All Products].[Drink].[Alcoholic Beverages].[Beer and Wine]} 
	+ 
	{[Product].[All Products].[Drink].[Beverages].[Carbonated Beverages]}'  
MEMBER [Measures].[Count] AS 'SUM( {[Categories]}, [Measures].[Sales Count] )' 
MEMBER [Measures].[Count A] AS 'SUM( 
	{[Product].[All Products].[Drink].[Alcoholic Beverages].[Beer and Wine]}, 
	[Measures].[Sales Count] )' 
MEMBER [Measures].[Count B] AS 'SUM( 
	{[Product].[All Products].[Drink].[Beverages].[Carbonated Beverages]}, 
	[Measures].[Sales Count] )' 
SELECT 
{ [Measures].[Count], [Measures].[Count A], [Measures].[Count B] } ON COLUMNS, 
NON EMPTY DESCENDANTS( [Customers] ) ON ROWS   

FROM   

[Sales]