Multiple Explicit Proxies

I think a better approach is to use   single vdom and set  a loopback as the explicit proxy  something like this.

e.g

  edit "loop10"

        set vdom "root"

        set ip 1.1.1.100 255.255.255.255

        set type loopback

        set explicit-web-proxy enable

    next

    edit "loop11"

        set vdom "root"

        set ip 1.1.1.101 255.255.255.255

        set type loopback

        set explicit-web-proxy enable

Than you can assign  one exa-proxy address to  the LAN and the other to the guest. Just make sure they are reachable.