You could get a Port, and connect that to your Yamaha, and just group the rooms that are the Playbase and the Port, and you’d get the tV audio on the speakers connected to the Yamaha, albeit slightly delayed. If you couldn’t hear both at the same time, it would be fine. 

Thanks- my ultimate goal is to get rid of the Yamaha and “clean “ up the wall.

Understood, did that about 10 years ago myself. The challenge is supporting both systems at once. For me, I kept the receiver a year or two longer than I should have, it was acting as an HDMI switch for an older TV. But I was lucky, I had already ripped most of my music, so playing from my BAS worked well on the rest of the Sonos speakers, and my PLAYBAR worked for the TV. 

So you have two separate systems? Playbar for tv, and Amp for wired speakers?

No, not any more. I used to work for Sony, so got pretty good employees discounts, so I had a fairly nice A/V receiver connected to a nice TV (at the time) that was connected to a PLAYBAR. This was shortly after being introduced to a Sonos, I already had a PLAY:5 in the kitchen, and a PLAY:3 in the bath. As I recall, I got the pair of PLAY:1s for surrounds at the same time as the PLAYBAR, but had to wait for the finances to cover the SUB. I listened to music for a while on the A/V receiver, but eventually just used the Sonos. At that point, there wasn’t much need for the A/V receiver and speakers, and I needed the floor space, so they got sold, and now I’m strictly Sonos, with two 5.1 systems, and a plethora of PLAY:X and Ones scattered around. 

Got it. I am looking for something that may not be possible. TV through Playbar, outdoor wired speakers powered by the Amp, and the TV sound getting picked up by the AMP also. 
Is splitting the hdmi cable a possibility?

Why couldn’t you just group the Amp with the Playbase connected to the TV set? Since the speakers would be in different locations, and not really audible simultaneously (i.e. you couldn’t hear both, unless you’re standing in the doorway between the living room and the outside), you wouldn’t notice the slight delay between the two. I actually used to do this with a pair of PLAY:1s in my kitchen, and my PLAYBAR in the living room. While I was occasionally cooking, I could still listen to the play by play on my poor football team (sadly, I’m a fan of the Washington DC team, for way too many years) while the TV was still playing in the living room. It wasn’t an issue unless I was in the hallway between the two, where I could hear both simultaneously, something that only occurred when I walked back and forth.

The Playbase can send the tv sound to the AMP if it’s in the same group?

Correct. 

That would mean the Amp is set up as powering the “surround” speakers, and wouldn’t achieve what your attempting to do. 

It would run wired speakers outside, you are saying that would not work?

There’s two ways to set up the Amp. One is bonded to your TV room for surround speaker use. When streaming music, there’s a setting in the app that allows you to use the surround speakers as full stereo speakers, rather than just ambient support for the sound bar. When bonded, all the speakers will play in sync, because they’re the single room that the TV input is part of.

The other way is to have the Amp set up as a separate “room”. Then, when grouped with the sound bar, the stream will be a stereo representation of the front signal of the TV. It will also be delayed by 75ms, because it is not “bonded” as part of the same room, but grouped. Any grouped room will have that 75ms delay when you’re grouping with the TV input. It’s due to the way that Sonos is coded, and the way they “jimmied” in the TV aspect much later in the process.

And to be clear, it is not my intention to cast aspersions at the way Sonos added their TV input to the system. They did an outstanding job of it. I’ve got two PLAYBARs myself, and am quite happy.