It’s possible to use the SAP-built-in load balancing. The following can be found in the documentation:
“In Connection Parameter define whether the connection should be established to a specific application server or via a balanced or group selection.”
I think it’s specified very similar to the settings made for the SAP GUI.
In addition it’s possible to run specific R3 jobs on a specific SAP application sever, even load balancing is used. This can be achieved by specifying the “Target system” in the Jobs attributes: