Multiple QNAP NAS's syncing?

[ZACHM]

I have a small office and we are considering getting some QNAP TS-251+ units.
The thought is to place one at the office and connect to it as a mapped network drive.
The other units would be placed at our houses (There are 3 of us), with the hope that we can sync all of the files between all of the devices? So like a 2-way sync, but between 4 NAS's, is something like this possible?

The thought is that gives us several off-site backups, and if someone can't make it into the office for some reason they could still work from home if necessary.

Internet speeds are not great around here (0.5 to 2mbps upload speeds), so accessing the files remotely would be very slow. But if after saving the file if it takes a little while to upload to the other units it would be ok. But we have some large files that we need to access that change rarely, but our software needs them to run. So having those locally would help greatly.

Am I able to do this, or do I need to approach this differently?

 

[sfx2000]

It's in the friendly user manual - see rsync

http://docs.qnap.com/nas/4.1/Home/en/index.html?remote_replication.htm

 

[ZACHM]

Thank you for the link.

I think what I am interested in is the RTRR.
I read through that and I see how to set it up for 2-way synchronization, but not for more. Would I need to setup the office NAS as a "primary" device, then setup separate 2-way syncs with each of the other 3 NAS's?

Say User 1 changes a file at his house, would that sync to the Office NAS, then the changes are noticed on the office NAS so it syncs to User 2 and User 3?

We have a static IP at the office, would we also need to have static IP's at the houses, or can you run something like no-ip.com? Never mind that one I found the answer: https://www.qnap.com/en-us/tutorial/con_show.php?op=showone&cid=24

 

[sfx2000]

I read through that and I see how to set it up for 2-way synchronization, but not for more. Would I need to setup the office NAS as a "primary" device, then setup separate 2-way syncs with each of the other 3 NAS's?

It defines a 2-way link for simplicity purposes - so you need to build multiple two-way links to a single master...