Show Features within Initiatives in the Starter Roadmap

In the Starter Roadmap, I like the way I can add a Feature within a Release, so the Release is displayed in the Roadmap with an arrow. When I click the arrow, the Release expands to show the Features that are planned for the Release.

Unfortunately I am not able to do this by adding an Initiative, then having that expand to show the Features that are associated with the Initiative. If I try to drag a feature over an Initiative that I have added to the Roadmap, it doesn't allow me to add it within the Initiative - it forces me to select a different area on the Roadmap.

If I had this capability, I could build a Starter Strategic Roadmap where a user can view the Initiatives planned for a specific time period (without displaying all of the child Features). The user would have the option to expand an Initiative to view the child Features. This would allow us an ability to more effectively manage and display a strategic roadmap to our stakeholders.