Yes it is possible, in the TV room settings for the Arc etc; there are toggle switches to Autoplay the TV audio and to ungroup on playback.. in any event you can ask SVC (Sonos voice control) to group and ungroup the rooms - Alexa voice services will do a similar thing too with Alexa ‘enabled’ groups, but that’s a little more complicated to explain.

I would guess Sonos voice control coupled with the toggle switches will be your simplest option.

If you use Apple iOS too, there are 3rd party apps, like Soro, that will also group/ungroup rooms using the Siri voice assistant. So lots of options to have this working and in any event there’s always the Sonos App as a ‘fallback’ option to group/ungroup rooms.

Thanks Ken for the detailed answer. 
 

Are you saying that I can make the Arc ungroup automatically, but every time I want to play music through all speakers I need to do something to group both virtual rooms together again?

Yes. It takes one click or 3 or 4 spoken words, and 5 seconds. I'm not sure why you seem so horrified by this prospect.

Short of inventing a speaker that can read your mind, I'm not sure how Sonos could reduce this burden.

@Dankerzz86,
 

As an example, If you were playing music through all speakers ‘grouped’ and you then powered on the TV/Arc (& surrounds) .. those speakers (Arc/Surrounds only) will switch to playing the TV audio and ungroup from your Fives. 
 

Then say later, you wanted to play music to ALL, you’d just say “Hey Sonos, group yArc Room] with AFive Room] and all would group together ready to play your music.

If  you were to use Alexa voice control and Alexa ‘enabled’ Groups, you do not even have to instruct Alexa to group the rooms, she will know to do it automatically once you’ve set up the group in the Amazon Alexa App.

In the attached screenshot (showing an Alexa Group) the user just needs to give a ‘play’ instruction to any of the Alexa devices in the first section of the group. 

"Alexa, play some music”, just as an example

Note: Speakers in the first and second sections of the group will ‘duck’ their audio to hear the user voice instruction.

Playback then occurs on all speakers listed in the third section of the group - they automatically group themselves together in the Sonos App and begin playing.

I hope that helps you to understand things, but as mentioned earlier, there are a number of ways to achieve what you are looking for here,

You may also find this helpful. It’s a link to the SVC syntax so you can see what you can do with Sonos’ own voice control assistant, which you can install to the Arc via the Sonis App:

https://support.sonos.com/en-us/article/list-of-voice-requests-for-sonos-voice-control

Both Alexa and SVC can be installed/used side-by-side too.

That’s very clear, thanks Ken!