Items are all grouped under one, it's rather quite a mess. However, just know that usually items are grouped by when they are released. Such as, you'll find Coral Beach items grouped together, Snow Hill items grouped together, Tapasco items grouped together, etc. generally. Newer items will be found later down the line. So.. yeah. Good luck. ;o!
Also, try doing a mass-extraction. (don't try to do too many at the same time if your computer isn't up for it though)