User Manual Pioneer AppRadio 2 (SPH DA100) 

I've heard that you could use a Chrome cast but not too sure. The S6 doesn't have MHL capability on the USB output, meaning it can't deliver HDMI which is required to allow the phone to screen share with the Pioneer SPH-DA100. Well that's how I understand it after spending hours on forums. If the Chrome cast does work please can someone let us know.

There is no output but you could always split the hdmi input from the phone meaning every screen sees the same image. But this has nothing to do with the appradio anymore offcourse... so you should look for a hdmi splitter...