[galaxy-dev] Choosing which nodes to run on for a whole history (Galaxy cluster)

I'm setting up Galaxy and Torque with my cluster and I was wondering if I could set it up so that nodes could be assigned for a whole history. This way I can re-run histories on certain nodes for benchmarking runtimes. It seems that the closest I can get with the built in functionality is specifying nodes on a per-tool basis, which is good but it would be painful to have to specify this for each tool I use in a pipeline each time. So how difficult would it be for me to add this feature, and which files should I start with in the code base? Or have I misunderstood and this is actually built in? Thanks