The two groups of tv stations are 96 degrees apart , that is a Very Wide angle of reception for most directional antennas to receive , a little too wide. There are a few antennas that do a better job of receiving tv stations at a very wide angle. Here is one I recommend give a try , Winegard HD7000R antenna , aim the antenna at about 48 degree magnetic compass , half way between the two groups of stations. Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing/pointing.html. I also recommend a indoor distribution amplifier , A ChannelMaster CM3414 , 4 way distribution amplifier. Three of the outputs of the distribution amplifier go to the 3 tv's , the one output port that has nothing connected to it will have a 75 ohm terminator screwed on to the port. I recommend using new RG-6 coax on the outside and new RG-6 coax to replace any other coax that might be bad. Here are places to buy antennas and etc. ,
http://www.winegarddirect.com ,
http://www.channelmasterstore.com ,
http://www.solidsignal.com ,
http://www.amazon.com ,
http://www.starkelectronic.com ,
http://www.3starinc.com