In VC setup a virtual machine network ( port group ) to handle vm traffic for each class C network. Assign them to the same virtual switch ( image 1)
In mine NO-VM Network handles 172.16.206.x and No-VM Network6 handles 172.16.6.x

On the Veeam server in lab setup create a network mapping for each address

See the “6” added after each name in production network and isolated network.
Then setup your network settings

You can skip the third nic, this is a third network.
It should now work.