I have come home from college, and although my dad is usually good with this, I fear he may have made a mess of our network. There is a 5th Gen Airport Extreme. Wireless connected to that is one 2nd Gen Airport Extreme, putting out 5GHz, and 2 1st gen Airport Extremes putting out 5GHz. We have one main connection (I'm assuming 2.4GHz) and a separate one for 5GHz. All the expresses are connected to the extreme under the option "join this network". Here's the problem. I understand 5GHz doesn't travel very well, and so when I hookup my systems to 5GHz, I very often get interruptions, even though I have one of the extremes in my room. But then when I try to hook them up to the 2.4GHz connection, it is too slow, and HD streaming is impossible. What would be a good way to sort this out? Is "join this network" the correct option for the extremes? Should we just set up a single network that does both 2.4GHz and 5 GHz? Can you extend the 5GHz network? I am usually tech-savy, but I am not sure what do here and any help would be appreciated.