It's about a Scrum Team. PO and the couple of developers. They do well every time, when task is clearly defined and only technical part is to be done. It gets complicated when there is a need to work with a fuzzy epic.

Epic is big. Inside of it, there is almost nothing but the idea. There are many customers and it is very hard to find a pattern, a statistical representation of the customer, so there is a need to merge many points of view into one solution. There is also much to be done with it, but the problem is how to process it in the Scrum? (the idea should be described, technical obstacles should be defined, prototypes/solutions should be proposed, checked against legal issues and finally: selected, solution should be understanded/described, stories created and etc.) 

It can be done by arranging several meetings and working on the subject, but it looks like a solution which is outside the Scrum process. On the other hand, putting it into the Scrum would create several tasks connected in cascade pattern (ping-pong with multiple players) and many of such tasks would be incompatible with the Definition of Done. 

Any help would be appreciated. I fell I am missing something obvious, yet important.