Filter on Childern of Parameter with Dimensional Data?

I’m relatively new to BI (10.2.1) and am working with TM1 cube data.

I would like to take the value from a single select parameter prompt and filter on the children on the of selection (including the parent). By filter, I mean use page sets to display one page for each filtered element.

In the Detail Filter area of the query, I have tried multiple permutations of syntax like:

Children ( [Ledger_Subclass].[Subclass].[Subclass] in ?pSubclass? )

but have yet to find a solution that BI likes and produces the desired results.

Any help would the greatly appreciated.

– John