Are the 2 green zone are one the same NICs?
If not, don’t worry with the routes.
Go in the Firewall object:
After creating the two CIDR objets, go in the Firewall rules, to create a new one, to accept all traffic from the first CIDR objet to the second CIDR object.
An a second rule, to accept all traffic from the second CIDR objet to the first.