In addition to my MacPro's internal hard drive, I have two 1-Terabyte drives installed in my MacPro. These will be used ONLY for Photo files. One has all of my current photo files on it, while the other has not been used. I simply want Time Machine to back up my one drive to the other. Nothing should be more simple.
But ...... even though I can do this, Time Machine also wants to back up my system hard drive. I don't want to do that. I simply want my one drive backing up to the other. Can't I do this? If so, how???