Hub and Spoke - LAN to LAN

Hi all,

looking for a solution to interconnect (LAN) 100 Branches to a central HUB (LAN). Each branch consists of a commercial Firewall and redundant ISP connection.
Here is a quick sketch of an example of one Branch and the Hub.

In case ISP1 goes down, traffic must be routed through the remaining ISP2. The failover is handled by the Firewall.
Can ZT be used to connect the LAN Branches to the LAN of the central Hub? If yes what is required?

Thanks
Roland