How to permanently remove some app purchases?

I purchased some "free" games.

Unfortunately, all of them are of poor quality.

I want to permanently delete them from my purchase history -> The problem is that each time I choose "Check for available downloads", it sees that these 31 apps are not on my computer and starts downloading them. But I don't want them! Ever! It wastes my time cancelling the downloads so I can download my new purchases.

How can I delete them permanently from my purchase history so iTunes never downloads them again?

I have the same problem with some music albums too - I purchased some entire albums since some songs I liked were available only as part of the album. The songs I didnt download start downloading each time too (and I have to cancel them as I don't want them.).