How about this,

If it's a dialogue between the Subjects, Cody is on the right, Gershwin is on the left.

If it's a dialogue between the Subject and the Agent, the Subject is on the Right, Agent is on the Left.

If there is intercommunication between, say, 2 subjects, and 1/2 agents, Agents stay on the left, Gershwin in the center, Cody at the far right


Or would this be complicating things? :p