Multidimentional topCount, how to?

Hi,

I have a multidimentional model and need to do a crosstab with top five ranking. I used a detail filter in the top level of the hierarchy, then inserted this hierarchy as a row in the crosstab. The result is that it filters the first level of the hierarchy, but when I drill down in the report, the lowest levels are not filtered by the topCount function, and that’s the functionality I need.

How can I get the topCount function to apply to all the hierarchy levels?

Thanks.