But as far as I can see, in the Import of XLS Files there are two different regions, Nodes and Edges. And furthermore, the user doesn't have to use the same Cells for the input.
What would be the big deal, to put in an optional 3rd imput-row or something likt that - containing information to which group each node belongs?
or - at least - for "automatic grouping" add a way to select an Attribut as a Base for the Auto-Groups.