The title for this question might not make a lot of sense, and for that I apologize.
I am currently working on setting up electronics inside a school bus to RV conversion I've been working on. For the head unit, I'll be using a Raspberry Pi, which will be the source of audio. I want to have two "groups" of speakers - one for sound inside the bus and another for outside. My end goal is to be able to a) use only the inside speaker group, b) use only the outside speaker group, or c) use both speaker groups at the same time.
What I am imagining is having some sort of buttons/switch setup between the amplifier and speaker groups that will allow me to specify what groups will be receiving the audio signal. Based on my searching, the first things that really sticks out to me a 1-2-both battery switch used to charge either one, another, or both batteries off of a single alternator. Obviously that's not correct for this application, but it's at least a start.
Very much looking forward to any and all suggestions, I'm pretty open to anything. Thank you!