It is indeed possible and have already been done, and a new version is available on the ui.worldofwar.net site:
http://ui.worldofwar.net/ui.php?id=3835
(On this site I only found an outdated version.)
The addon is called LootFilter and what it basically does is that according to certain configurable rules it will erase the unwanted looted items from your inventory. Combined with auto-looting enabled, it will imo do just the thing you want (provided that you have free bag slots, since the addon does not selectively loot, rather erases those freshly looted items from the bag, that conform tothe drop rules).