Welcome to the forum! And to answer your question, yes you can train a GSD to understand that a particular collar signifies certain types of behavior, but I'm not sure you'd gain anything by making that too fine grained. Many service dogs are trained to know that when they're wearing a certain harness they're on duty, when the harness comes off they're off duty.
It's not the size of the dog in the fight, it's the size of the fight in the dog. Mark Twain