This one is so well known it perhaps doesn’t need to be listed here, but just in case …
either at the trailhead or ahead of time, suggest that folks might share certain gear items to save weight. A very common one is that one person brings a stove and the other a water filter or other treatment --- “you heat my water and I’ll treat yours”. In some cases it could make sense for certain group first aid items be shared among the group, and of course as the trip leader it’s possible you’ll have an item or two for group-wide use that you might rotate through who carries that (a more complete first aid kit with some extra discretionary items is the primary example).
Tents can be a particular benefit, for the group as a whole as well as for the individuals. If you think there might be very limited camping space for one or more nights along the way, it’s a good idea for you to try to arrange that folks share tents ahead of time (four 2-person tents can fit in a space that eight solo tents would not). If you leave this until the trailhead, there’s a good chance that folks won’t be sharing tents. Note also that you should suggest that earplugs be carried.