I would not promise to "lead" 45 people - I mean, unless you've got the status of the Tour de France, 45 people in one group is dangerous, so it's just as well that it's unlikely to actually happen. When I've been on rides like that I figure out where I'm going to ride (and if it's not me, somebody rides sweep), and we figure out places to regroup.
I lead our Saturday Saunter, and do whatever needs to be done for our club's big fundraiser ride - it takes a whole *crew* to (wo)man it.
We also have some "unsupported" group rides, but no promises are made. This means people end up being happy because we do try to take care of folks, but the description is "no food, no sag, just maps - bring a friend or just tag along." There are always a few mother hens (of any gender ), though there are also always a few tales of woe... but generally, people know that's part of the adventure. It's *not* a supported ride.