You can use the HU to select the unit you want to turn all lights on , then select the next unit and turn all lights on , as long as you don't turn them off they will stay on. I have done this to balance out my circuits with the KILL-A-WATT. I think the most units that I have turned on at the same time was 5. When you get done you can go back, select the unit and turn the lights off for each unit. This works for the CTB16PC's not sure about other controllers.
Just read Mr. P's post and he is correct when it comes to the CTB16PC controllers.