Well, Jemarr and Anastasia should be able to extract the origin point of the geth message once they've made some progress on decoding it. I imagine that there would be a mass relay linking Toril's star cluster to the vicinity of the Hydra Nebula relay. If it had been dormant until recently, that would explain it being unexplored, since we don't just go opening random mass relays, but if the geth are using it now, then it'll be open and we can use it to get to Toril.