Add Release/Schedule Phase expandable grouping to Features Roadmap

I use the Project template and love the Features Roadmap - except that I cannot customize enough. Some of my projects have a lot of activities in the phases and when I do an Activities Roadmap, I would LOVE if it would arrange the Activities into their respective phases on the big list - where the phase can be collapsed in the same what it can be on the Gantt view. This would dramatically enhance the stakeholder use of this roadmap in my case. I am not proposing that the phase be calendarized per se - just that the activities under the release are also grouped into their phases and that this can be expanded or collapsed.