Good morning andrewtoris,
Thanks for your question and welcome to the community!
You are correct with having wires to be split, or at least separated.
The key to reconfiguring your upstairs and downstairs switches depend on two main things: installing 3-way switches/wiring and tracing your existing wiring to make sure your new switches are independent of the hall lights.
As for hiring an electrician, it is entirely up to you, and always a best practice to at least consult one if you aren't sure of any wiring steps.
3-way switches control fixtures from two or more locations, which is what you want for your stair lights. They work by way of using 2 hot wires, called travelers, instead of 1 so the lights can go off when you want them to. Since you want them on each end of the stairs and the house is already finished, it may present a challenge to change out the existing wire in your walls to 3-way wiring.
You will need to do some investigating to find out where the source of the wiring is coming in, and how you can wire up the lights above the stairs with the new 3-way switches. This is why without seeing your electrical connections in your wall, I can't tell you what is the best solution for you without needing more information first. Clicking on the image below will link you to our project guide page on the basics of putting in a 3-way switch...
To see a video version of this, click on the screen shot below to see it in action....
Connecting wires is the step that gets most people frustrated, but if you have accessibility, playing it safe by turning off the power to the lights, you can trace the old wires and switches to reconnect and make a 3-way switch. A good helper on the project is a voltage detector to ensure you are working safely and securely.
As explained in the supplies for wiring a 3-way switch below, there are more than one way to connect them together. Luckily, we have a great book in our stores called the Wiring 1-2-3 book that has great illustrations and more in-depth coverage that shows various scenarios when it comes to hooking your new switches up. You don't even have to buy the book, you can find an associate in the store to make you a copy of the section on 3-way wiring, so it's a book that shouldn't be overlooked.
Please update us if you have any more information or questions regarding your existing wiring setup. Bottom line, if you can trace the wires in the wall and split them independently now and update your wires/switches for the stair light, you are able to do this project.
Regards,
aboveaveragejoe
