Apparently they think that anyone off the street knows how to do all the work required to set up addl dishes and coax and recvrs ...
The money you are saving easily pays for that. Hire a third party installer for a few hundred bucks and he comes by with a dish and wire and installs however you like. He's not asking questions, he's just doing a job.
And they may all have already had Directv do their installs for free. If you, your brother and sister already have Directv you could say "hey how about if I get a couple more DVRs from Directv, I give them to you, you guys cancel and we all split the bill?"
It also might be done with neighbors, just run a cable between houses.