Cloned computer to second PC - folder sync to keep track of seen movies/shows?

Hi. I've cloned my main XBMC computer (Windows 7) to another computer and want to sync them, so that the movies/shows I've watched on either one will be marked as watched on the other one. The files itself reside on a NAS. As I said - the two computers are identical except from the computer name. Is there a folder/file I can sync between the computers that updates this?