Virtual WAN under phsyical WAN port

I'm very new to networking, and I'm a bit over my head. The current situation is we have two firewalls (Firewall 1 and Firewall 2) and two different WANs (VDOM Prod = 1.2.3.4/32, VDOM Nonprod =5.6.7.8/32) on physical ports on Firewall 1. There are no WAN connections are Firewall 2, so when there's a failover, we lose connection to the outside.  

My end goal is to have a physical port on each that can support both VDOM WANs without adding more physical WAN drops to the greater network. 

So, here is my concept:
Firewall 1:
Physical Port-1 1.2.3.4/32 (Prod VDOM)
   VLAN 5.6.7.8/32 (NonProd VDOM)

Firewall 2
Physical Port 2 5.6.7.8/32 (NonProd VDOM)
   VLAN 1.2.3.4/32 (Prod VDOM)

Is this a feasible solution? Should I make the connection identical?  

Thank you for your time.