My brother is incredibly similar to you. He isn't living abroad, he's only twenty miles away, but he deliberately avoids coming over because he doesn't like our mom or dad. He's perfectly happy to babysit my younger brother or go see a movie or walk the dogs with me, but whenever Mom or Dad comes a'callin, he says, "Uh, I have to work tonight."
Even though he actually only works for about two hours in the morning, one at night, and gets free room and board. [He's an aide for a LFA man who lives alone; he makes sure he doesn't miss the bus or forget to shower or brush his teeth. Or try to go out wearing a purple and green suit as a tribute to Heath Ledger on a work day.]
I don't blame him, and I don't blame you. You probably shouldn't cut them off entirely; just give them a call every now and again and say, "Just calling to say 'Hi.'" Or, if it's more comfortable, use snail-mail. There's not lots of room to get agitated, you don't have to deal with them when you don't want to, and you can always pick and choose what you feel like responding to.