Look under the Network Settings section of the following link. You can set Autodetect Network Interface and Autodetect HTTP Address to false and manually specifiy your settings - the .19.x addresses in your case.
inductiveautomation.com/support/ … ttings.htm
I know why you might use a different network for database or server communication, but I’m not following why you would use a dedicated interface with a crossover cable between 2 ignition servers. What would this accomplish?