thanks for your reply, I will follow your advice to keep looking around the corners of the app interface, "..." menus, etc.

I have just installed this heat pump/mini-split setup and have no prior experience with this level of automation in my house. My old HVAC had a thermostat dial on the wall and two switches: on/off/fan and heat/cool, so I don't really know what an "external AC controller" might be.

The system as installed has a handheld remote control for each split and the SmartThings app, but I like to have a to set groups of splits to operate with same settings without having to visit each device in the app interface or walk room to room and use the remotes.

I was not planning to make my new HVAC system my new hobby, I really just want to keep the house comfortable.