Quoting from the above blog post,
Navigating such a large tree to connect with your ancestors can be tricky. We recently added a new feature called “Labels” that will, as it continues to develop, provide a new way to place your ancestors in better context.
You’ve used labels on other sites and in apps to easily organize and view similar types of things. You can now add labels to your ancestor’s listing in Family Tree to honor their accomplishments, signify their involvement in a group, or memorialize their profession.Here is where the label function shows up on my Grandfather's page.
In looking at the options, I was able to add the following label
When I click on the label, I get a link to the website listing those who served in the military.
It would be nice to have a feature that would let us browse different categories. There is apparently some lag time in connecting the websites. Perhaps they are all being reviewed.