@10127-Martin
In my understanding, you need to re-use the data grabbed by one test case and iterate another test-case over it.
In this case, you can create a ‘mockup’ test data (with some default values).
CSV or internal (XML) are easy to parse file formats.
Since the test data are in fact physical files on hdd (and since the test data is already defined you should know the exact path and name), you can use some system commands to parse it’s content when the first test case is executed and update the data into the given file.
Not sure how safe is this procedure or if it will actually work, but you can try.