Sadly, it's the difference between "you can group them and it brings Airplay to your your entire Sonos system!" (which is what they said e.g. at https://blog.sonos.com/en-au/airplay2-coming/) and "you can bond them and it'll make your Playbar an Airplay 2 target!" (which is what we all wanted to hear).
It was pretty weaselly worded if you ask me, since the difference between grouping and bonding is a technical nuance specific to Sonos's proprietary system so I am not surprised at your disappointment. It's not reasonable to presume that people outside of the Sonos echo chamber would know the difference.
There were some clarifications buried in the forum for those that could find them e.g. https://en.community.sonos.com/home-theater-228993/playbar-vs-playbase-in-an-airplay-2-compatible-home-theatre-setup-6799021/index1.html#post16240175 but again hardly reasonable to expect a regular consumer to dig that deep.
To your specific question, they have not indicated publicly that a future update will supply this behavior.
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