Originally Posted by JoeyBike

I would imagine if you put a mile or two between each cyclist that would do it.

There is no SOP for group rides generally. You should post your question over in the Roadie forum though. Those dudes often ride Giros and such every weekend and have tons of experience with everything group related. They usually ride in one or two large packs (pelotons) to take advantage of slip-stream drafting. No way are they going to spread out to accommodate motorists. And they don't care what motorists think. But you should really ask them.