You know I think you ladies are right.. I shall just let it be. And I appreciated the point about car repair shops not being able to "police" bad drivers. That gave me a fresh look, and that's exactly what I needed! Once again, my TE friends have come through with sage advice just as requested.

I am however going to call the police non emergency line and request that they have an officer at the 4 way stop on saturday morning. The ride is very predicatable route and time wise.
This is an organized group, and they even have a name for themselves, though I would not go as far as to call them a club.
My neighbor (not a cyclist) had a novel solution of sorts..
She suggested that I go out and buy the brightest neon poster boards I can find,and place signs with "gentle reminders" along their route (yes they follow the same route weekly).
She suggested the first one they would encounter to say
"Good Morning Cyclists. Have a safe Ride, and please follow traffic laws" in BIG bold letters.
and then to post "WARNING CYCLISTS Stop sign ahead, please slow and prepare to stop"
another one "CYCLISTS narrow road ahead, please ride single file"
etc..
She even suggested a "Thank You cyclists for visiting our community. Please ride safely so we can see you again next weekend."
Her suggestion was to not tell anyone about it, and just be the stealthy sign lady out posting signs in the dark of night.

I prolly won't do that, but I have to say it is a novel idea.