Sync multiple seafile servers, including users

Hi all,

I’m not sure how to handle the following setup or what the best practice is.

The goal is to have at minimum three seafile instances sync with each other, not only the data but also the users. Is this possible?

The setup would be one seafile instance on a hosted server and the other two in the local LAN at two different locations. At the sites, the internet connection is too slow to always use the instance in the datacenter.

The users should be able to use the same account and depending where the are connecting to the available instance.
I think this could be solved via local DNS servers. If the user is in LAN A he should connect to the seafile instance A, if in LAN B connect to seafile B and if on the road connect to seafile “Cloud”, always with the same data. It is no problem if the replication takes over night.

As I understand I cannot use the real-time Backup server as it has no front end enabled.

Additional would one license be enough as the same users would be on all instances or would I need to license each instance?

Thanks for your help!