Hi.
You may find that
PureSync does what you want. I use it to mirror my working directory structure on my main windows box across the network to the linux fileserver, and from there to the laptop. It also handles replicating copies of the acronis backup files. It took a little while to set up, but works completely reliably in the background.
You can set it to monitor a specific directory for changes, and after a period of time since the last change, make the copy. It has a lot of other options and modes as well.
pca