Take a look at the last 2 answers in the frequently-asked questions list to see why things don't behave how you'd expect them to. I think it worked better in Alpha 13 or 14--which is the last time I tested it out to create a family the way that you describe here. Sometimes the order in which you add the relationships can make a difference, but I couldn't find an order that worked the way you want it to.

I'll try to take a look at it.

I managed to get it, you make the kids brother and sister...then add one parent. then add marriage and make the other sibling the child of the spouse.

Originally posted by Bobbi Deniro:

I managed to get it, you make the kids brother and sister...then add one parent. then add marriage and make the other sibling the child of the spouse.

I did it the same way but it was still buggy. During the game it turned out that apart from the parents I added and which were my colonist there were some other, imaginary parents somwere out there :) Some of the siblings/children got mood lowered because "my father X died"... but your father is right here, next to you, eating a lavish meal! "Naah, man. I had a father and he died!"

Mod is absolutely perfect but this part isn't working flawlessly ;-)

The playthrough i did it in however, the first 3 or 4 wanderer joins events were all my leaders extended family...his mom, dad, uncle and a long lost brother i think it was or it was his wife's mother. It was hilarious