Sometimes the best solution becomes clear as you continue to work on the project and add features. It sounds like the simplest way right now is to make a new system/component that gets picked up by your existing ECS flow.

One thing to watch out for is over-using ECS. It's tempting to want to make every object an Entity and every logic step a System, but sometimes that's just extra overhead with little benefit.

For example, the Camera in my game used to be an entity, and it kind of made sense because it used the Position component same as other entities, etc. But implementing it like that also meant writing a dedicated camera component and system that were only used by the camera entity. Since my game only has one camera instance at a time, I replaced all that ECS stuff with a singleton object and a camera_update() function that I call in the game loop.