Fortunately, bawpotter decided that we need a family tree going on here. But sadly, there was a time elapse and Ben and Jen turned 10 and all the adults turned 40.
Bob= Father of Jen, Brother of Judy, Husband of Jill
Bill= Father of Ben, Brother of Jill, Husband of Judy
Ben= Son of Bill and Judy, Nephew of Bob and Jill
Jill= Mother of Jen, Sister of Bill, Wife of Bob
Judy= Mother of Ben, Sister of Bob, Wife of Bill
Jen= Daughter of Bob and Jill, Niece of Bill and Judy
I hope this family tree helps you.