There are certainly other workarounds for this problem, but I just wanted to share a solution I found to achieve the idea suggested in the subject line.

Certainly one could use the cresc/decresc plugin, but I didn't want to fool with MIDI data. Plus, I also wanted each 2 counts to get progressively loud, not a smooth crescendo spaced over 8 counts. The lines connecting the notes are slurs, not ties. You'll notice in the attached recording that there is a space at 5.5s and 6.5 sec, as a result of the ritardando for some reason. To fix this, I gave each half note it's value in EDUs (512 in this case) and that forced each buzz roll to sustain to each down beat.

This is obviously a pretty specialized case, but I figured I'd share for everyone to stow away in their bag of tricks.