Create a hierarchy using different columns with levels

[ale_BI]

I have this situation in my file, where I have columns for each layer of the hierarchy, and I would like to create a 'normal' hierarchy with 2 columns (father and son) to use. I tried to append tables but I seem to miss the point in every function I try. Does anyone have any idea? 

[ronrsnfld]

Please add an example of your expected results in two columns, based on the table you present in your question.

[lbendlin]

Read about the PATH functions, ragged hierarchies, and ISINSCOPE.