When our kids (who are now "adult kids") left for college, we created a Yahoo Group where we could email, share pictures, provide them with their vaccination records or other somewhat sensitive information, even chat (although that didn't work for everybody, since the kids' massive bandwidth was shared with many other users). Assuming your younger kids' computer use is in plain sight, this might be a good option for your family, allowing them to spend as much time at your family's group as they want so they can stay connected to their distant siblings.
We encouraged everybody to share whatever interested them, from jokes to pictures of their dorm rooms or silly links. (You'd want your older kids to be mindful of the little ones' limits, of course.) We have some amazing pictures of The Kid with her waist-length hair in a sleep-induced knot, and one of Kid Two in drag. (So pretty--not!)
Many times we sent pictures of home to various homesick kids so they could see their rooms (still in shambles, just as they'd left them), the turkeys at the bird feeder, the huge icicle hanging off the gutter, or the birthday cake they could not share.
We still use our Yahoo Group, although we're in less-constant touch now. It's the fastest way to send this-made-me-laugh material to the family without intruding on their time.
Maryn, hoping this has some potential for your situation