I currently have the Sonos Arc hooked up to my TV and I would like to add two additional Sonos One SL to have surround sound system. I do also have Sonos Amp present in the house for outdoor speakers, but that’s not related to the TV room set up I am trying to accomplish.

When clicking on the Arc within the Sonos app and pressing surround sound, the only option that comes up is to pair it to the Amp. 

How do I just connect the two Sonos One SL which I current have paired to gather to the Arc to play the TV?

I have also created a group but that only works for music and still more manual that I thought it should be. I play music, it first plays on the two that are paired and then I press the group I created and all three speakers play together.