I'm not that worried about the risk from group rides, but my club has suspended them, & now out of the habit.
I did do one a couple of weeks ago, & it was fine, except for my not-great fitness level.
I heard a qualified expert say recently that you could be in a car with someone who had COVID and be pretty safe if you just cracked all the windows.
If that is true, then being in open air on bikes with presumably non-sick folks has got to be much more safe.