I don't really mind how big a group I ride with but there's a few things that I ensure happens when riding in groups of any size....
that everyone knows from the get go that the larger the group, the slower the ride
make sure everyone knows the basics of group riding, establish some basic ground rules
safety first and don't be afraid to take steps if someone is being a dickhead
I'd ridden solo, I've ridden in with a small group of mates, with strangers, with demo groups consisting of thousands. If I don't like the way things are going out, then I take action...that could be slowing down, stopping, having a chat, agreeing to meet at the rendezvous point and then making my own way...etc etc..
But it's all riding :) just another way of experiencing it, a bit like track days vs off road vs touring