Routed LANs with IPSec as it in OpenVPN

  • I am quite new to IPSec, please feel free to route me to right IPSec resources.

    I implemented routed LAN over OpenVPN as it described here:

    Where clients are pfSense boxes and server is a cloud VPS:

    Corp-A LAN=>pfSense-OVPN-client-A    =>    [VPS: OVPN Server-with public IP]    <=  pfSense-OVPN-client-B <= Corp-B LAN

    Only there are more LANs and clients, but idea is the same. I used OpenVPN iroute to expose client's routes on OpenVPN net. Plus pushing nets to the clients.

    That's perfectly linking A and B, making their firewalls closed. No public/routable IPs are needed for the clients, static server IP is enough.

    Life is perfect, though for various reasons (mostly, political, "official and widely accepted VPN" blah blah) IPSec is required. Is the scenario above is doable with IPSec?

    Or I should not waste my time?