Outdoor sonos speaker volume control

Hi,

I have two monitor audio ceiling speakers setup in my outbuilding with a Sonos Amp and Sonos sub.  The system sounds awesome! I would now like to add 2 additional outdoor speakers to the system and would like to limit the volume of this set independently of the indoor speakers.  
 

Is there a speaker pair that I can buy where I can restrict the volume on the speaker itself?  I just wanted the ability to have a low outdoor speaker volume.

I understand Sonos doesn’t allow the independent control of different speaker pairs…

thanks