My mother is one of eight, so weddings have always been an occasion for the whole family (33 people) to get together in one place and take a picture. So I am planning on asking my mom's side to stick around after the ceremony to take a family photo at the altar of our church. And since I am doing it on one side, I also plan on doing it with my father's side of the family if they want (potentially 18 people), and with my FI's extended family, if they want.
Assuming we go through with all these pics, some people may get held up into the cocktail hour. Originally I thought we'd do a ceremony from 3-4 and cocktail hour starting at 5 to make sure everyone can get there, but having read how much guests hate gaps, I think 4:30 is the better option.
I am fairly certain my mom's family will be on board with the picture, but is it rude to start the cocktail hour without them and others in the families? Am I forcing them to choose picture or party? We will probably have around 200-220 guests, so even with the big families and wedding party hanging back there will be a lot of people to accommodate at the cocktail hour.
Also is it strange to make an extended family portrait some kind of optional activity? I was thinking I'd just talk to my dad and FI's parents to see if they are interested in a picture with their siblings, and if so, they could communicate that to the others.