Does iMac support sound through thunderbolt?

Hi I'm currently using a thunderbolt display with my retina macbook pro. I'm thinking about getting an iMac instead of the thunderbolt display.

I know you can use the iMac as a secondary display for the rMBP just like the 27" thunderbolt display. But my question is can I use

the iMac's headphone output on my RMBP through thunderbolt? I think this would be really convenient, hope my question makes sense

Basically I want to have my iMac hooked up to a pair of speakers. But I want to be able to play music through these speakers from my

retina macbook pro via thunderbolt and the iMac.

Just want to make sure this is possible before I purchase. Anyone know if I can do this?

Thank you!