@jbenfer Thank you for bringing your question to us here and welcome to the Sonos Community. Unfortunately, I would not have any supported setup options to provide you to get the computer audio out to your Playbar. Let’s see if any folks in the Community can reply with any viable workarounds for you.

Since you list a One and a Play:5/g2 in your system the simplest option would be to Airplay from the Mac to either and group it with the Playbar.

If video/audio sync is required you may need to wire the Mac directly. You could use the laptop’s headphone jack, wired to an ADC (analog-digital converter), which can then send optical to the Playbar. If the Playbar is already connected to a TV it would make sense to get an optical switch to flip between the two sources.

@ratty I have airplayed and grouped the Playbar but I do not want sound out of the One so I have to mute it and then unmute and ungroup when I am done.
 

Any analog-to-digital converters you could link? I have primarily seen digital to analog converters. 

A quick search produced:

https://www.amazon.com/Musou-Digital-Optical-Toslink-Converter/dp/B01HGHNCMW

https://www.amazon.com/Digital-Converter-Musou-Aluminum-Coaxial/dp/B07TXSW43V

There could well be more. None should cost more than $20.

A further option, should you not wish to be tethered by a cable, is to Bluetooth from the Mac to a Bluetooth receiver that possesses an optical output.

@ratty thanks for the links! I’m not sure why I wasn’t finding those. Also, the Bluetooth idea is very thought inducing.