How to include members with specific children in MDX query cross join?

I'm new to MDX, and I have following scenario. I have to calculate revenue across specific department (product dimension), specific store (location dimension) and across specific time range.

I have my cube levels as follows.
Product <- Department <- Item
Location <- Region <- Store
Time <- Year <- Month <-Day

Say if I have following members

[Product].[Dairy].[Oak Farm]
[Product].[Dairy].[GV]

[Location].[US West].[LA]
[Location].[US West].[CA]

[Time].[2015].[01].[01] : [Time].[2015].[02].[01]

Then I should get result as where in Product should include only GV and location should include only CA

2015-01-01        US West       Dairy       $100
2015-02-01        US West       Dairy       $100

Any help would be appreciated.

Probably several ways depending on exact requirements.

 SELECT 
   [Measures].[SomeCubeMeasure] ON 0,      
   {[Time].[2015].[01].[01] : [Time].[2015].[02].[01]}*
    Exists
    (
      [Location].[Region].MEMBERS
     ,[Location].[US West].[CA]
    )*
    Exists
    (
      [Product].[Department].MEMBERS
     ,[Product].[Dairy].[GV]
    ) ON 1
FROM [yourCube];

Edit

To create a measure that just looks at certain stores you could use something like this:

 WITH MEMBER [Measures].[Store1and2Measure] AS
    Aggregate
    (
      {
        [Store][Region1][Store1]
       ,[Store][Region1][Store2]
      }
     ,[Measures].[SomeCubeMeasure]
    )       
 SELECT 
   [Measures].[Store1and2Measure] ON 0,      
   [Location].[US West].[LA] ON 1
FROM [yourCube];