It's not all compartmentalized, by any means. As a contractor working in Afghanistan, I'd often have military or civilian counterparts ask me about system locations or movements that was more their lane than mine to monitor. If you have the expertise, they depend on you.
As opposed to contractors, most guvvies / military are general managers or worker bees, not specialists, and their ability to master or even be conversant in certain types of work is extremely limited. Contractors will often become the shadow 'brain trust' of a government organization. In fact, competing government agencies are often more comfortable sharing with contractors than with each other, since we're not 'a threat'. This lets us be even more versatile and connected.
There are some operational meetings you won't be invited to, and details you won't be privy to while they are happening, but they'll certainly consult you before and after. Many companies provide in depth reports or reviews which become government resources, used as though the military / government officials themselves wrote it.
On the other hand, their odds of guvvies seeing private company proprietary information was approaching zero, unless it was for something related to a new contract proposal. It's definitely a one way street, as far as the information flow, but the government data is the easier to obtain, by far.
Thanks for the info.
Did you represent a certain type of equipment?