I have to manually quit a group ride in progress to join another group ride as it starts.
If I miss the start time I am screwed.
Often times I quit early but zwift is so slow switching joining group rides that I quit one ride early just to miss the next group ride or I get lost at the start line as everyone has gone.
Furthermore I often like the 1st group ride more than the second one but have no choice but to quit early as I cannot join the second ride late.