How should I model the database for this problem? And which ORM can handle it?

Answer 1

This might not quite be what you're looking for but...

I find that using Microsoft Access is a quick way to create a functional database model (although limited) and to test out different query logic.

Using MS Access would then allow you to create your tables and then try out different iterations of how all the tables/data would link together quickly without needing to write lots of code.