How can I hide leaf level members of a ragged dimension ?

I need to hide leaf level members of a ragged dimension. Any thoughts ? My original approach was through roles (security), but I am open to other suggestions.

Maybe I need to generalize this. Is it possible to hide lower levels of a heirarchical dimension ?

Specifically, I have our corporate organization, with the following heirarchy:

CEO-->ExecVP-->VP-->Director-->Manager-->Supervisor-->Employee.

I need to be able to hide measures associated with leaf-level employees, and also selectively at the small group (supervisor) level. But security seems to work backwards--I can hide top level aggregations, but not the lower level.

Any ideas ?