Allow Digital Content admin to a few individual units.

I have several sites listed by cities.

I'm trying to limit digital content admin rights to just a few units at each location. When I go to the specific device, I'm not able to just give to each unit. it's grey out and to the far right, I see: Using Account Settings.

I don't see an option in account settings to list digital content admin settings per device.

I don't want to give access to a Floor settings, I want each unit.

thanks