SmartThings allows you to create a “virtual device” which will be treated by SmartThings just like a physical device even though it only exists as a listing in a device table on your account.
So if you create a virtual switch, it will show up on the list of switches in your mobile app, and you can tap its entry to turn it on or off. And you can have turning the virtual switch on or off trigger other events in SmartThings. You could also have your virtual switch turned on or off automatically just like any of your other switches.
Here’s the FAQ on creating a virtual switch:
First, though, it sounds like you might be able to use the intro to scheduling as well:
