Dual Wan failover using P2P microwave connection and site to site VPN

  • Hello all,

    I have two sites which are 1km apart. Both sites are connected using a P2P Microwave connection. Site A is connected to Fiber internet, Site B shares internet through P2P to Site A. On a good day everything is fine. Occasionally, the Microwave P2P connection breaks down due to heavy rain, snow or humid condition, as a result Site B goes offline. Currently, both sites use Juniper SSG5 as the firewall.

    The Plan;
    -Site B will get its own dedicated Fiber connection with a different ISP.
    -Site A and B will then be connected through OpenVPN.
    -The Microwave P2P connection will be used for failover.
    -Lan1 can have internet access as well as access to Lan2.
    -Lan2 has no access to internet or Lan1
    -Of course Junipers will be replaced with pFsense routers.

    The Setup;
    -WAN Fiber ip: x.x.x.x/32
    -Microwave ip:
    -Lan1 ip:
    -Lan2 ip:

    -Wan Fiber ip: y.y.y.y/32
    -Microwave ip:
    -Lan1 ip:
    -Lan2 ip:

    The Question:
    How can all this be achieved using pFsense routers.
    -Looking online, I can probably get OpenVPN to work.
    -I can probably get the failover to work.
    -Not sure how to get Lan1 to communicate with Lan2 on both Sites