MDX Cascading Parameter

I have this MDX query below that I will use as a parameter in my report.  This query allows me to select the 'Current Outside Sales Name'.  I also have another parameter that allows me to select branch.

What I would like is to select my branch then have the 'Current Outside Sales Name' parameter show only those sales names within that branch.  Currently it doesn't matter which branch I choose I see the same list of sales names which is all of them.

I have figured out how to make parameters cascade within the same dimension hierarchy but I'm having trouble because the 'Sales Name' and 'Branch' are in two different dimension hierarchies.

Any help would be GREATLY appreciated.

WITH
MEMBER [Measures].[ParameterCaption] AS [Current Outside Sales].[Current Outside Sales].CURRENTMEMBER.MEMBER_CAPTION
MEMBER [Measures].[ParameterValue] AS [Current Outside Sales].[Current Outside Sales].CURRENTMEMBER.UNIQUENAME
MEMBER [Measures].[ParameterLevel] AS [Current Outside Sales].[Current Outside Sales].CURRENTMEMBER.LEVEL.ORDINAL

SELECT
    {
        [Measures].[ParameterCaption]
        , [Measures].[ParameterValue]
        , [Measures].[ParameterLevel]
    } ON COLUMNS ,

[Current Outside Sales].[Outside Sales Name].ALLMEMBERS ON ROWS

FROM

    [Sales]