3-way light switch to outbuilding

[ArtcoInc]

I am in the USA, and I have an older house (built in '41), with the original tube & post wiring. Nothing is grounded. There is a 3-way light switch by the back door that controls both an outside light on the corner of the house, and a light in a detached garage. There is also a 3-way light switch in the garage that also controls both these lights. Overhead wiring from the house to the garage feeds both power to the garage, and the travelers for the 3-way switches.

I have recently upgraded the electrical service to my house, and have added a 150 amp feed to a sub-panel in the detached garage. The wiring is underground, just the power to the sub panel, with no room to run additional wires.

In the future, when I have to remove the existing overhead wiring from the house to the garage, I will loose the 3-way light switch function. Per code, the garage light must be powered from the sub-panel in the garage, while the outdoor light will still be powered from the main panel in the house.

How can I configure a 3-way light switches, so that I can simultaneously control the lights (both in the garage and the outside light) from both within the house and the garage, keeping in mind that I can not run the needed 3-way travelers.

 

I do not know how your system works, but what I am thinking is something like:

1) Two 'hubs' (or whatever you call your system), one in the house, and one in the garage.

2) Two 'relays' (or whatever you call your system), one on the garage light, and one on the house light.

3) Two 'three way light switches' (one in the garage, and one in the house), which 'talk' to *both* hubs, switching on (or off) *both* lights (in the house and the garage), in a 3-way fashion.

For any wireless system, I am concerned about the distance from the house to the garage.

Thank you.