Thank you for your reply Jack :)
I have looked at a few of those importers, but when i make the csv, i'm not sure how i get the relations between the tables transferred as well.
When i make the csv, it puts the tables in the same sheet, after each other, so that's not good, cause the importer reads columns.
If i import the tables separately, will Wordpress by itself figure out the relations from the ID in the main table ?