Thanks to @DanHolloway who noticed the new feature and posted in one of the other “Feature Request Boards”, Ring listened and did it! I got all excited so I immediately went to my Ring App to link mine also! But, I was briefly disappointed when I tried to do it because I did not initially see any change in the App. It initially appeared to still only make the cameras record when the alarm sounded . . . until I looked more closely. So, yes, the camera sirens CAN be linked now by:
Menu > Devices > Alarm Base Station > Base Station > Linked Devices > Alarm Sounding >
After selecting "Alarm Sounding", this is where I was briefly disappointed because I thought it was still just to select the cameras to only record. Then I noticed the "Explanation-Point" Icon, just right of the "Camera" Icon. Now I understood that by selecting this "Explanation-Point" Icon, it links the camera's siren to the alarm too! So after selecting "Alarm Sounding" then:
Select “Explanation-Point” Icon for the cameras you wish to sound off their siren with the Base Station > then “Save”.
Wonderful! Thank you Ring!