Report Builder 3 Filtering with Recursive Parent

Hey all, I have a bit of a problem that I can't seem to figure out... I have a dataset that contains financial information, with which i've joined an account tree and brought in a field called "parent". When I build my report I set the recursive parent and it produces a nice indented view of my financial information like one would expect with hierachical data. Now, this report is currently using all of my data... I need to add a parameter so that I see only certain departments at a time. When I add this parameter, it takes out my "recursivity".. (ie: only shows account-level.. no rollup/parent information) I would guess this is because those rollup rows don't contain any department information which match my filter - I get that, so I moved the parameter from the tablix to the dataset... but it still didn't work... Any ideas/workarounds/suggestions... Would be greatly appreciated. Thanks!