You can create 1 file with all the level, and create multiple actions each for one hierarchy, and you can add all these actions to the process. When you run the process after publishing to the dashboard, it will ask for only one file to load.
With all the Parent-child relations for all levels. Update a each hierarchy a time, L1, L2 and so on. You can combine all these actions in one process. going forward you only load this one file to update all hierarchy.