You could create a virtual switch to simulate a virtual contact sensor and in rontalley’s example, that’s what would be turned off/on in the logic.
Aside from that, you can use CoRE in different way from rontalley’s example to accomplish the same thing. For example, I have 3 motion sensors in my office which control one of the lights. My CoRE logic says that if any of the 3 see motion, the light comes on. The logic states that when ALL show no motion, wait 2 minutes and then turn off the lights if no additional motion is detected in that 2 minute timeframe. So basically, with CoRE logic, I’ve created a virtual motion sensor using 3 separate physical motion sensors.
If you’re having reliability issues with these contact sensors, I’d make sure they have solid connectivity to the hub (you may need a repeater of some sort added between them and the hub) and maybe consider adding a Monoprice tilt sensor to the garage doors. Mine have been super reliable.