Forced to connect my optical audio cable to directv box

Hi, I'm a new Sonos owner (just received it yesterday!). I bought a playbase and 2 Ones that are on their way later this month. After setting everything up, I couldn't get audio to come out of my playbase while watching tv via directv. So after connecting the optical audio cable to the directv box (rather than the TV as the instructions say), the sound started working. The problem is that when I switch to my Apple TV, I can't get any audio to come out of the playbase at all (obviously because the cable is connected to the directv box). Does anyone have a solution to this? Do I need to buy an hdmi splitter? Ideally I want to connect my optical audio cable to my TV (like the directions say) so that no matter what input I'm on, the audio comes out of the playbase... but it seems like the cable box is posing a problem with this...