Part of me says "fuck em, let em rot in their JWism" but then the sensible part says something different. Maybe on your next newsletter, you can personlize theirs just a bit to express how dissappointed you are that they are acting in such a way. But, you're going to continue to include them in you newsletter emails because they are family and you love them as family. If they choose to disregard it and not read it, that's up to them. Maybe in time, they'll come to see the folly in how they are treating their family and will reach out to you.
I'm reminded of something I've seen on TV recently. I don't remember the plot of the story, but a young lady had cut off all contact from her father for years and years. He continued to write, but she never opened them. Instead, she saved them in a box. Much later, when she realized that she didn't have all the facts, she went back to the letters and read them. Years of hurt and pain were caused because she refused to hear his side, to listen or read his thoughts and feelings. Now, she had a change in heart.
This can and does happen with JWs and ex-JWs. Look at the thread started by a new member who came here a few months ago to blame "us" for breaking up their family, but today, after much research realized that something was wrong with the JW belief. They came back to say that they learned something and that things weren't as they thought previously.
Maybe one day your family, my family, anyone's JW family will see it and seek us out to repair the damage done. But we have to be there, ready to accept them back as readily as they are to be a part of our lives again.