This is a place where the VCA drops the ball. Assuming you have, let's say, 8 drum tracks that are part of a group and connected to a VCA track. You would THINK that hitting the Record button on the VCA would enable all the drum tracks, but at the moment, that does NOT work(as I think it should
). However, once you enable Record on the 8 drum tracks, from that moment on, the VCA Record button WILL toggle record on the 8 drum tracks(until you close the session and come back, at which point, you are back to the beginning)
Now, re the term "STEMS", that would be more appropriate to using AUX tracks and routing groups of tracks(like all the drums, or all the BGV's)
VCA's are really just a way to control the overall level of a group of tracks(a "stem" is a recording of a group of tracks into their own "submix", which is also referred to as a "stem"
)