I don't know the answer but have a similar problem. I guess that you entered your grandmother and grandfather and his brother. Later you want to add the second marriage with a person (the brother) already existing in the tree. Right? And I cannot see that this software allows you to create a relation with an existing person in the tree. Catch 22...
My problem is two couples of brothers and sisters that married cross wise. One man to a woman, and this womans brother married the first mans sister.
I would say that the answer to our problems is the same, how to create a new connection/relation with an already existing person somewhere else in the tree???
