Only by un-bonding the Play:1’s and setting one up as a single room unit, which is not really practical. The “surround setup” is effectively a single entity. In Sonos terminology, Grouping refers to creating a temporary set of speaker rooms and playing sync’d sound to those speakers in those rooms, whilst surround speakers and subs are Bonded to their “control” device (the Beam, Arc etc). 
 

But, you can boost the level of sound to (both of) the Play:1’s v the Beam for music playback, if that helps? 

Actually, I cannot boost/change the sound of individual speakers. Sonos says that if I tap on the sound bar in app, it will open individual volume option. But in my case, it is not happening. Tapping does nothing. Not sure if it is an iPhone only feature.

I think you are mis-understanding what Sonos means by groups.
 

Sonos uses “rooms” to define a speaker or a set of speakers. In your Living Room you have a home theatre setup. The volume control for Living Room will raise or lower the volume of all of the speakers in that home theatre configuration. There are sliders you can use to change the ratio of sound coming from the rear surrounds and the front Beam and there are separate settings for when the input is TV or music. There is also a setting for Sub volume if/when you have one. But because they are all bonded as a single entity, there is only one volume control for them all. This is not a group. 
 

If you have a Five in another room called Kitchen, you can group the two rooms together to play the same source. The volume control in the app will then change the volume of the whole group - ie all the speakers in the Living Room and the Five in the kitchen. But if you tap the volume control individual volume for the rooms in the group will appear. So, if you have six rooms, all grouped, six (labelled) volume controls would appear for you to adjust volume in just one room specifically.