Trying to use my iPhone 3GS as audio output

This might sound a little convoluted, but here it goes.

I'm trying to get some use for my iPhone 3GS, and i though i might be able to connect it to an audio system and stream music from my Mac library to it. If i use iTunes, ideally, i could use my iPhone 5S to control iTunes, and therefore, control the music that's being output through the 3GS.

Is this even possible? Using my iPhone 3GS as audio output from a Mac, preferabily using iTunes instead of 3rd party app?

Thanks!