Nice! A system expansion! Will it go upstairs? If you have 5 or less devices, you should put one device per zone, and label each one with the device name or location. A lot of users seem to do that.
Each device will have its own zone and if its going Upstairs I don’t know you’ll just have to wait and watch system test ten to find out 
If you are using electromechanical horns, I will love you forever.
I am going to try for you. 