XML and hierarchical support in Grid

I am trying to use the hierarchical element of the grid, but so far I have not found a way to bypass the datatable in a generic way. I have a list of serializable object that has the following format:

The format of the file is equivalent to have a file with a list of element, each including a element which itself includes a element. I could use XSLT to transform that object/XML file into a file with a flat structure with the following tables , and (the same way Northwind database has orders, products and suppliers table). Once the tables created I would then create relationships between them. The problem with that approach is that in the case of change, the data has to be translated back to the original type of object. It consume time and resource. Is there a quicker and easier way to handle such file ?