Dear Rookie,
unfortunately, I’m not aware of what exactly you want to achieve and which functions you are currently using, but I’m glad to hear that you found a way to make it work. Though I don’t understand the issue with loading them separately as you could just use c++ features to iterate over all existing vtu files as mentioned here: https://stackoverflow.com/questions/612097/how-can-i-get-the-list-of-files-in-a-directory-using-c-or-c
Best regards,
Jan