It really depends on the consistency of the photos and maybe more importantly, the colour of the subject. PS has the ability to do selections on colour range, so you record your actions on processing a single image to create a PS Action that you can then apply to other images.

If this works, then you can apply the action in a batch process against all your images and let it run.

If your images don't allow for the easy color range selection though, you won't be able to automate it like this. Manually doing the selection will be very time consuming.