Well, if you just randomly select one face and do as I suggested, you'll get through it a whole lot more easily than selecting a ton of faces and cutting them away. Try it out! I'm pretty sure it's as near as you're going to get really; I've split an OBJ into it's 2000+ component pieces this way in an afternoon and I wasn't sure what I was looking at. Utilise the hide and lock object features as well and I'm sure you'll get there easy enough.
