The XP indicates that the Dispatcher has "patched" the two Talk Groups together. The Dispatcher is able to connect two (or more?) TG's together for better coordination. Or it allows one dispatcher to handle two (or more?) TGs' during slow times. Example, they often tie/patch Davis Co LAW-01 (TG9408) and 02 (9440), in the evenings. This way, one dispatcher will handle both "channels". This is done at the Dispatchers Console. During the day/heavy use, they use separate TG's, so the dispatcher does not get overwhelmed.
I think (assuming again) that the change over is still a couple years away. When the time comes, we will adjust as needed.