We have a project with 170 epics, and we would like to group them around specific themes in such a way that our product owners can reschuffle the priorities of these themes and the priorities of the epics within a theme.
Is there a way to setup a project / rapid board such that
a) A product owner can reprioritize on theme and epic level in the product backlog
b) When the team lead works on planning the sprint, the stories are prioritized according to the epic priority. For instance when epic 1 has a higher priority then epic 2, all stories of epic 1 have a higher priority than the stories of epic 2
What is the best approach ?