Can't use outside speakers without inside being on help

I have a 2017 Outback (made by Keystone). We may have the same media/radio unit. If we do, it will look like 3 buttons at the top (that turn blue when on). Those control the zones for the radio/speakers. Zone 1 is inside living area, zone 2 is bedrooms and zone 3 is outside. By pressing those buttons, I am able to turn zones on and off.

I hope this helps.