Port Forwarding for Barracuda appliance

Hello, I've just recently upgraded my Sonicwall firewall to a Fortigate appliance and I have a question on opening ports to allow communication to and from my Barracuda backup appliance on our LAN.  On the Sonicwall I could create a bunch service objects (TCP, UDP) and then I could put these into a group.  I could then create two access rules: one for WAN-LAN and one for LAN-WAN traffic.  I would finally have to setup a NAT policy to have any incoming traffic point correctly to the Sonicwall.  I've been trying to set this up on the Fortigate using virtual ips but it seems like the vips get tied to an interface which means I'd have to create a group for the WAN then repeat the group again for the LAN.  Is this the best way to do this?  Thanks for any input.