Make Windows Update Install Only Security Updates Automatically?

After the news earlier this month about Microsoft forcing the Windows 10 upgrade on people who don't want it, my sizeable extended family has been coming to me for a solution. They don't want to be guinea pigs this early in the Windows 10 release cycle, but it looks like Microsoft may not be giving them a choice. My reading of Woody Leonhard's advice is that the only way to ensure the upgrade doesn't happen is to disable Windows Update, but that seems extreme. I want my family to install security updates, but I don't relish the idea of explaining to them how to install just those and hide the less-desireable updates.

The ideal solution would be to have only security updates install automatically, but it looks like it's easier said than done. I've looked at third-party tools like Autopatcher and Portable Update, but a security-only option doesn't seem to be very standard. From what I've read, Microsoft doesn't even package security updates separately, sometimes mixing merely Important and Recommended updates in the downloaded CAB file. I wish I could get them off Windows, but it's not an option. They use Windows at work or school, and don't want to go through the process of learning another OS. Maybe the current situation with Windows 10 will convince them eventually, but they need something now. I would really like to come up with a solution before the next Patch Tuesday on October 13. Do any of the more knowledgeable Slashdotters out there have any advice?