Suggestion to be Sync all time!

I have a PR4100 NAS, and we have 3 laptops. So, we want to have a unique folder in the NAS, and maintain sync all the time with the 3 laptops, this mean, any people can work with files and always have the lasted files version in our NAS (lasted updated files).

I was thinking that could be possible, installing a WD Sync in each computer and sync in the same folder in the NAS.

The other thing is always work or edit directly in the NAS networked folders/files, but we dont know if the speed is enough, etc.

How do you solve this? or recommendations?