UPDATE: My original question really boils down to this: If I set a file to not accessible (e. g. with "chmod 000 file"), would I give out bad pieces to other Peers? And why so?
ORIGINAL: I have some huge torrents, where each has 1000 files. I only need like 200 of them. Is there any possibility to skip the remaining 800 files? I can easily create a list from all the unwanted (or wanted files) from a database.