A group ride over this distance will be far easier if you can run with the group's pace... big difference between a group ride and a solo ride of this distance.

My solo pace on my touring bikes can be as good as 30kmh over 100 miles and sometimes even better but running with a good group can push the speed up into the high 30's and low 40's depending on the group dynamic.

Position on the touring bikes is set for comfort and usually get off the bike feeling pretty great.