Rally Software

With the Milestone enhancement to be able to select a list of 'projects' for each, I am curious about how the existing Milestone reporting will work.  I have Project (portfolio) areas that share milestone dates but would like to see their milestone reporting (e.g. milestone burnup) separated for only their Project area.  Do we need to set up separate milestones for each portfolio area?  Or can we share the milestones and count on the reporting to only report on items in the milestones within the selected Project hierarchy?

For the record, the Milestone reporting appears to include data from all artifacts tied to that milestone, regardless of which Project I am scoped to.  This will be problematic in some cases where the timing of milestones is the same but separate portfolio areas want to see how their own area is progressing.  I see a need to toggle back and forth between 'milestone reporting at the Project level' and 'milestone reporting at the workspace level' for a specific milestone depending on the audience.