In this case, two brothers marry two sisters from a different family. In
this example, the two brothers are John and Danny and the two sisters are
Marielle and Rosanne.
This is the same very similar to a marriage between cousins. You use the
mouse to select simultaneously the husband and the wife, and you
invoke the Family Wizard. As soon as you click on the OK button of the
Family Wizard, you have created a union between the husband and the wife.