I think I would look for a slower group too. When the organizer told you the pace is 17-18, does that mean a 17-18 mph average or no faster than 17-18? There's a huge difference. I also know from experience that if the group is all guys, they will push each other to go faster. They can't help it, they are men and everything's a competition. There would be too much testerone for me and wouldn't be much fun--unless I could beat them up the hills