It could be that the circuits upstairs are fed by a non-armored cable
at some point. You could replace the breaker on that circuit with a
GFCI breaker. That's what I did in my house because I have non-ground
romex. I replaced the 2 prong outlets to 3 prong and put in GFCI
breakers Most states approve this method and is code, plus you'll have
protection now .