Option to schedule by Epic rank rather than Story

A common use-case for us is for a plan to be built around the sequential scheduling of Epics, rather than the order of Stories on a backlog.
There should therefore be an option in the configuration settings to choose between

A) Schedule based on Story Rank

B) Schedule based on Epic Rank

For example, Epic A might relate to the Initial Investigation phase of a project, Epic B to the Detailed Investigation, and so on.
While you can use an Agile board to order the underlying Stories into the correct sequence, it would be much easier if there were an option in Portfolio to simply schedule everything under Epic A first, then everything under Epic B second etc.

This would also cover the current problem that newly-created Stories always go to the bottom of the backlog and therefore are scheduled last by default, regardless of what Epic they belong to. For example, in the scenario above, if during the Initial Investigation stage a new work package/story is identified and created under Epic A, you would want Portfolio to automatically schedule that alongside the other Stories under Epic A.