You could use SCOPE in this case
SCOPE([Measures].[Your Measure],[Dimension].[Hierarchy].[Member1]);
THIS = Your Calculation 1;
END SCOPE;
SCOPE([Measures].[Your Measure],[Dimension].[Hierarchy].[Member2]);
THIS = Your Calculation 2;
END SCOPE;
where,
[Measures].[Your Measure] is your calculated measure
[Dimension].[Hierarchy].[Member1] , [Dimension].[Hierarchy].[Member2] are your calculated members on the dimension.