Nested Controller with partial for each controller

Hey guys, i am using a single app written with backbone right now. But that isnt ideal because of async file uploads is kind of pita.

for example i have an email client like Mail.app: on the left side i have a scroll down list of my mails/conversations. on the right side i have the full mail shown up.

I am stuck how to handle the state of the partials with nested routes. Anyone an idea?