A Simple Task no doubt, but for me?

[jepoore]

Google Drive has the flaw that you can't install it on an external HD. I have 4 PC's (they never give up I keep them happy, oldest is 7 years old) and a tablet. I have Verizon DSL because the only other choice is Comcast, no FIOS available. I have this D-Link Router that has the neat feature of having a USB port and I have a 40G HD plugged in. The neat thing is every pc has access to it with no problem. No homegroup or anything needed and even though I am using a 2nd old router for a repeater for 2 older devices that won't work on the newer encryption. So I add all my files and new additions to the Verizon USB HD from each computer. BUT, that 40G HD needs to be backed up and preferably as things change realtime, not every so many hours or days. Like Google Drive would do if it could be installed. I understand that FreeFileSync can detect and change things as they happen too? Could someone easily tell me how that could be done in the simplest way possible. ie If I add or change a file to the Verizon Drive from one of the pc's, then FreefileSync detects it and backs it up on the Google Drive installed on my desktop local HD. Thanks so much! Apologies if I have not been adept at explaining what I'm looking for. Jack ":-\