AVH521-EX Audio

Hello all, this is my first post and I hope someone can provide some input here.

I recently installed a Pioneer AVH521-EX car stereo in my Travel trailer. I have four speakers, 2 in and 2 out hooked up with the speaker leads through Pro Wire IW-101 Speaker switches. The purpose of the two switches is to control sound either in, out or both.

I have a TV in the trailer and was thinking of adding a small sound bar for direct sound from screen when watching movies. If I was to run not only the video out from the Pioneer " V Out" but RCA's from the Left and Right "Front Outputs", can I select sound from this output when in Video mode or will sound play on all speakers? Or none as all as I'm using the RCA and the speaker leads?

Thanks