How to make droplet always open a particular version of photoshop

I process a lot of images through the Photoshop Droplets. It often takes hours to complete. I've worked out recently that if process some files through CS 5 and some files through CS 6, then I can get all the files done quicker, because more of my multi-core CPU is being used at the same time. So I wanted to know how I can setup individual droplets that only ever open which ever version of Photoshop I assign to it.