So i have 1 Airport Extreme on office, and 2 Airport Express (one on my backyard and one in my room).. The iMac i have at my room, has the airport express is about 6ft away from my imac, and the Airport Extreme about 100ft away.. When i open my airport utility my imac is connecting to the Airport extreme instead to the Express in my room, how can i for it to connect to the one with more range?? ---------- rebooting the iMac did it, but is there a way to make it permanent???