broadcasting with macbook and imac I3

So i broadcast a radio show once a month, i use my Macbook pro with (traktor), to a NICECAST server. But with traktor i cannot broadcast a microphone, so i was thinking if i connected my pro to my IMAC I3 then the I3 to the (nicecast server) would that work, YES i think, now to do that can i just connect my headphone out socket to the input in the I3 will that then broadcast my show with microphone connected to my s2 traktor controller, your thoughts please