Hard Drive swaps on Macbooks

Ok folks....here is the situation. I have a (a) Black 13" macbook (identifier 3,1) with a 2.2ghz processor, (b) a unibody 13" macbook (identifier 5,1) 2.4ghz, and a 13" macbook pro (identifier 5,5) 2.26ghz. Macbook (a) is my girlfriends current laptop, macbook (b) is MY current laptop, and laptop (c) is a new acquisition. I would like to take laptop (c) as my new computer and give laptop (b) to my gf. Is it possible to just swap the hard drives in any of these models? In a perfect world I would love to be able to just open all of these computers up and take the hard drive from laptop (a) and put it in laptop (b), and then place the hard drive form laptop (b) drive in laptop (c), and throw the drive from laptop (c) into (a) and then sell laptop (a). I know it may sound really confusing....but I am sure that you all understand. Am I going to run into problems with this? I know I can mirror these drives if I HAVE to, but I am looking to save some work for myself here. Thanks in advance....

Other than having to read this riddle a 2nd time through to understand what you wanted to do, that shouldn't be a problem

Its doable

The only problem that you could run into, is trying to put an OS that's older in any of the OS's that the laptops shipped with.
ie If your black Macbook shipped with 10.5.8, you cant put a hard drive with OS X 10.5.6 in it. It has to be 10.5.8 or later
So, as long as you upgrade the OS's if the need be, there will be no probs.