Multiple family, I guess it could be called generational. I have 31 base families (I only meant for it to be about 10, but it kind of snowballed) that rotate each sim week, and watch how their lives intertwine. They can socialize with NPCs, but only marry sims from one of the other played families, and siblings can't marry into the same family, in other words ywo sisters can't marry two brothers. That rule may change later, but for now it's just to spread out the gene pool. Hopefully I can stick with it long enough to see how many generations it takes to get one big family tree.