Release Milestone based roadmap

I would like to be able to create a roadmap at our top most parent line that would automatically include all milestone dates added to any Release, under any workspace.

The idea is that I would be creating a way to keep our marketing department up to date with potential major release candidates automatically so that they can schedule marketing efforts around those releases.

The only way to do this currently is to manually go in to a roadmap and select milestones manually, which is not ideal.