Cracking office documents and other hashes using clusters?

I'm trying to figure out how I should go about testing this I just got donated 18 older hp systems that have 4 gigs of ram, and intel core 2 duo processors I believe that they are the ones that came out just before the I series from intel came out. So I'm planning on creating a cluster out of all of these as a fun side project, I do a lot of reverse engineering and I'm just now starting to get into the whole cracking the hash thing. I know how to run various tools like john and oclhashcat, but I have no experience as far as anything cluster related goes. I really would like to know what programs and commands I would need to run in order to do something like this. I have them all hooked up already on my switch so I'm trying to get some advice on what I should do next.