I have an older house, where running the new wires I need is challenging. I have a light that is on a switch at the top of the stairs, and I would like to add a switch at the bottom of the stairs also. So, my question is if there is any possible solution using smart devices such that I can maybe use a wifi lightbulb that talks to a switch downstairs, but also toggles if used with the current, upstairs switch? Or maybe both switches can be smart switches - convert the existing one, and make the new one a smart switch (but both on separate lines) - i.e. Have one smart switch directly in line with the light and the other totally separate?
Some additional details to better explain the situation is that the current, upstairs lighting is on a subpanel already upstairs. I can easily add the required power and switch to the downstairs from the basement. The issue is connecting the two disparate wirings to the same light.