We've done it both ways as well. One trip was 4 families all in the same resort, same building and floor. The kids could all hang out together, swim, etc. We decided before the trip what days, events, meals we were going to do together and then the rest of the time each family could determine their own schedule. The down side was on the days we were together, it was tough to get everyone out the door at the same time. My family likes to hit the parks early and we were waiting on everyone else, usually. Would I do it again...yes!
Last year, 2 families in different resorts. We were at the Poly and My Daughter, Son-in law and granddaughter were at SSR. This worked out as well. We met up at the parks and for meals but no one felt like they had to wait for anyone else.
This year, 3 families. We will be at the Poly and the other two families at SSR. We've determined what parks, FP+, and meals will be together and each family will go their own way if they want to outside of that. My kids are all young adults as are their cousins that are going so even they can do their own thing if they so choose. I'm sure we'll have a great time even though we're in different resorts.
Either way, do what's best for your family and don't stress...have fun and enjoy your trip!