Not the way that the Genogram sample was designed. That sample was designed for understanding the genetic relationships of various people. Adoptions (whether legal or informal) would not be considered.
I suppose you could design and implement something different. I know that many customers have done so, sometimes making dramatic changes. But I do not have their code and could not give it to you even if I did. And chances are high that you would have different requirements anyway. Every app is surprisingly different from each other.
Someday we will completely redesign and reimplement the Genogram sample, including the GenogramLayout, so that it better meets the needs of more customers. But not today.
I think in this case it’s possible to arrange the marriages so that they are wider than their collection of children. Then there would only need to be a straight link extending down from the “marriage” link to the child node. But I don’t know how well that will work with all of the other relationships that there might be with the parents or the children.