Yes you can, an what that is called is -Slaved. now the fta is easy just split your c & ku signals going into the 4dtv receiver an run them into a
diseqc switch that is hook up to the fta.
Now for the hard part with the 4DTV, 1st you will need to get a 0 to 12-volt switch (good luck on finding 1) then you will need to run a line from lnb on the dish that you want to go into the 4dtv, then hook it up to the 0 to 12v switch then the other IF lead going to the 4dtv will also need to up on that switch an short jumper back to the lnb port that you are setting it up for. BUT NOTE; that the 4dtv will ONLY support 1 switch, so you can either have it looking at 2 ku dishes or 2
c-band dishes, if you want to have 2 c an ku dishes that wont work with the 0 to 12v switch, but their is another way around that 2-old A & B switch, but then you got to get off the couch to switch it.. Good Luck