Could tie it to espionage as a game mechanic too. That is the sort of thing a spy should inform his government of. Spy's should give reports in a popup message of various things that you click on the espionage tab you want to be informed of.

To your point there should be a diplomacy option for allies to share information like this.

Gal Civ 3 is such a massive game, especially when played with 100 CIVs, I wish we had a Bureau of Information Tab we could easily check and uncheck things we want to be informed of, which changes for me at different points in the game.