This might half the time required. You say you have a VM already on the laptop. Get a handful of external ethernet adapters. I think the best number will be in the neighborhood of 4, but learn with 2.
Run the VM and have one adapter present in each VM. Connect to device inside the pump. Start the next VM. etc. This is still a 2-node network, each instance will have a "fail safe" in an error will stop the one instance. With a typical gas station having 2 double pumps per island having 4 connections means one island at a time. 2 connections means 1 double pump at a time.
Best part is the headache is all in the VM working properly, and should be transparent to the software and to the pump. I am sure you have a training system to practice on before taking this live to the field.