As far as I know, the Super Hornet demo teams do not have a discrete air-to-ground frequency. Most of the coordination done with demo teams is usually reading off flight data; in a two-seater, the WSO can handle that. All aircraft will be on the air boss frequency; the second radio may be set to air show discrete (PA feed for "live from the cockpit," or air-to-air used by the Tailhook Legacy Flights).
At the Indy Air Show last week, the East Coast team used the air boss frequency alone; the only comms during the demo were telling the announcer which maneuver was coming up next.