Except bureaucracies are going to do what they do. The offensive agency will hold back information, and when an attack occurs on the defensive agency, calls for bringing the defensive agency under the umbrella of the offensive agency will be made.

Brats fighting over resources while Mom just wants to sleep. It's not their fault, it's the nature of political organizations.

Sure, you could fix it with centralized oversight and stringent information sharing rules. But eventually you're either strangling them with rules or building one conceptual agency.