Auto Load USB System

We would like a system developed that would automatically load a file onto a usb pen drive every time it is plugged into a pc. At present we need to place a large numbers of the same file onto different usb pen drives and we would like to automate this process if possible. We would instruct the system as to what the files are and then when the system is switched on it will load those files onto a pendrive every time one is plugged into the pc. Serious offers only please.