Speaker Receiver Problem

I have a small room off of the garage for my projects and I installed a old speaker receiver with three speakers in the room and two in the garage. I have a chromecast audio for the input and I added a simple switch to turn on and off the speakers in the garage. The problem I am having is that when I have surround sound off all three work in the room but the two in the garage dont, and when surround sound is on the two in the garage work but only one works in the room. Can I wire the three in the room all tougher so they all work? Will wiring speakers together over load the receiver? Thanks.