The Naval Research Laboratory has published some interesting artwork that provides some insight into the configuration of the small Atlas-launched NOSS payloads of the 1970s and the much larger Navy Triplet launched on the Titan-4 in the early 1990s.
On a webpage entitled Naval Center for Space Technology Experience the following image is displayed.
This image is a bit puzzling, however, as it seems to depict four spacecraft, versus the three depicted in the other images
Unfortunately, this depiction is not terribly detailed, so it is a bit difficult to make out just how the thing is constructed. The good news, however, is that if one takes a look at NRL's Spacecraft Assembly and Test Facility one finds this much more informative image:
Some other images have also become available