You can direct payments, you just have to be willing to stay on top of it to make sure it gets applied correctly. They will first take any unpaid interest for all the loans, then whatever is left you can indicate which loan you want it applied toward. I did this in the past. Inevitably they didn't apply it correctly, so I would have to call and spend a bunch of time on the phone until they corrected it. Would suck to do each month, but I was just making extra payments a few times a year at that point. You should call and get the address for their special payment handling division (after about a year of playing this game with one lender, someone finally told me there was a different address to which you could mail in payments with special instructions that would supposedly avoid this problem). Worth it if your interest rates are significantly different.
