Crankin' - I know that exact intersection (very well). This winter, I had the same experience you described, but I was ON MY BIKE! And guess what? They still didn't move - spread across the entire intersection, and I had to go into the opposite lane to make my right hand turn around them.
BTW - I hope there weren't any NEBC jerseys in that group.
SheFly
"Well behaved women rarely make history." including me!
http://twoadventures.blogspot.com
No NEBC jerseys or CRW... and I was glad of that.
They were green and blue jerseys, with some black. Not sure which club this is; Metrowest Bike Club?