Query Designer Calculation

Hello Experts,

I have a query in which I have all my KFs in the columns and Division in free characteristics, which is an input from the user upon query runtime. I have to display key figure "A" for a specific selecion for Division that the user enters or display key figure "B" for all other entries. Is there any way of doing this? The key figure displayed will either be a regular KF or calculated KF depending on user entry for Division. I'm looking into Variable User Exit, but not sure how to implement this for such computation. The query is running off of a Multiprovider with multiple cubes combined. Any help would be greatly appreciated.

Leo.