I think you've made a good decision, OP. Sometimes, you do have to do what works best for you, even if other people don't find it as convenient. I think the thing is to really own that decision and be comfortable with it. Your sisters aren't going to magically change their point of view, especially with the history of you
doing whatever they
want. Of course
they would prefer that continue, it's all to their advantage.
So I think you just have to get used to saying, "This is what we're doing, you are free to join us if you want," and then drop the rope--if you can't compromise or the compromises they suggest don't work for you, "that won't be possible" and you just go on with your life. Not all sisters really have anything in common or are friends once they grow up, and wishing they were different sorts of people is just an exercise in futility.
I hate to seem harsh, though. Probably in your shoes I would make them other offers for later, like hosting them at my house in early spring or buying them a meal at a restaurant which is partway between our locations. Depends on the situation, of course. Or go out of my way to set up appointments to Skype with them, especially after the baby is born. Basically I would try to show that I want
to keep up with them, but no, I'm not just going to do it in whatever way they
want, I will give a little but they have to give a little, too. And if they don't care to continue the relationship
if they don't get their own way completely, well, then you know where you stand.