Also in a group ride you will need to add communications that you don't have solo. Signal your turns (and watch for others' signals), signal when slowing. Call cars and other items of interest. ("Babe up!") Call your location on turns and overtaking. Communications within the group greatly reduces the chance of wrecking.
I've clashed handlebars on a turn - no fall - and it was my fault for not making the other rider aware of my presence. I also fell off once on a slow climb, but that would have happened were I solo. No other problems (except maybe stopping at two beers afterwards; one group is ride with is self-described as "a drinking club with a bike problem"
).