Having node columns and branches columns

I would like to be able to modelise a tree data into an OR’s table.

With row/record, we can do that, but only with the first column (node) and second (branch) column.

I would like to have the possibility to create of modify the type of a column from standard (what we have now, just hold a value and error at the same time in its cells). That would require to set for columns a type node, and a related branch node, so the node column would have it's value be a ID for the node, and the branch column would have both a value plus a branch ID column.

I guess this logic already exist for JSON or XML import. But there is no way to manually built it in an existing OR’s project. Also, there is no technical documentation to explain how it's implemented… @antonin_d, maybe you could explain it a bit…

Regards, Antoine