2 extruders into 1 hotend config

Been looking for this answer for a while with no luck, I really did google this first I've got a Rostock Max V2 that I just got the hardware and firmware setup with the Y adapter. So I have 2 extruders that share a single hotend. I'm lost as to how to set it up so Slic3r only commands one temperature. Am I missing something? Or just out of luck?

On current dev from git.

Thanks
Cory

Great software, thanks to Developers and supporters!!!

So it appears the firmware handles the temp change of the hotend automatically. Now I'm completely clueless on priming towers

Quote
clytle374
So it appears the firmware handles the temp change of the hotend automatically.

Nope, that doesn't happen either