How to do dynamic calculations in MDX?

Rating Dimension:

(ID, MainVariance, MaxVariance, Rating, StartDate, EndDate)

  Rating Dimension values:

SELECT     1 AS ID, 0 AS MinVariance, 0.10 AS MaxVariance, 1 AS Rating, '01/01/1900' AS StartDate, '06/06/2079' AS EndDate FROM         ApplDim

UNION

SELECT     2 AS ID, 0.11 AS MinVariance, 0.30 AS MaxVariance, 2 AS Rating, '01/01/1900' AS StartDate, '06/06/2079' AS EndDate FROM         ApplDim AS ApplDim_5

UNION

SELECT     3 AS ID, 0.31 AS MinVariance, 1 AS MaxVariance, 3 AS Rating, '01/01/1900' AS StartDate, '06/06/2079' AS EndDate

FROM         ApplDim AS ApplDim_4

UNION

SELECT     4 AS ID, 0 AS MinVariance, 0.20 AS MaxVariance, 1 AS Rating, '01/01/2011' AS StartDate, '12/31/2011' AS EndDate

FROM         ApplDim AS ApplDim_3

UNION

SELECT     5 AS ID, 0.21 AS MinVariance, 0.50 AS MaxVariance, 2 AS Rating, '01/01/2011' AS StartDate, '12/31/2011' AS EndDate

FROM         ApplDim AS ApplDim_2

UNION

SELECT     6 AS ID, 0.51 AS MinVariance, 1 AS MaxVariance, 3 AS Rating, '01/01/2011' AS StartDate, '12/31/2011' AS EndDate

 --------

 Created a set in Cube as "RatingSet" :

 
RatingSet

{

[Rating].[Rating].[Rating] *

[Rating].[End Date].[End Date] *

[Rating].[Max Variance].[Max Variance] *

[Rating].[Min Variance].[Min Variance] *

[Rating].[Start Date].[Start Date]

}

 ------------------------

Calculation which needs to be made dynamic:-

IIF( ([Measures].[Variance Percent]>=0 and [Measures].[Variance Percent]<= 0.10) –--Variance Percent

                ,1

                ,IIF( ([Measures].[Variance Percent]>0.10 and [Measures].[Variance Percent]<= 0.30)

                        ,2

                        ,3 --Rating

                     )

)

i.e. Variance Percent will be 0, 10, 30, 50  etc… and Rating will be 0, 1, 2 3 etc…

---------

 I tried below, but not working:

WITH  DYNAMIC SET Test2 as

IIF( ([Measures].[Ownership Variance Percent]>=[Rating].[Min Variance].[Min Variance].members.Item(0)

and [Measures].[Ownership Variance Percent]<= [Rating].[Max Variance].[Max Variance].members.Item(0))

,[Rating].[Rating].[Rating].members.item(0)

,IIF( ([Measures].[Ownership Variance Percent]>[Rating].[Min Variance].[Min Variance].members.Item(1)

and [Measures].[Ownership Variance Percent]<= [Rating].[Max Variance].[Max Variance].members.Item(1))
,[Rating].[Rating].[Rating].members.item(1)

,[Rating].[Rating].[Rating].members.item(2)

)

------------------

Now, How to make it dynamic as above???????

Any help will be appreciated.

Please suggest asap.

Many Thanks in Advance.