Star Trek isn't so brazen about it, but it's kind of telling that outside the pilot episode, Deep Space Nine contains no overt references to Voyager, and Voyager in turn never mentions Deep Space Nine or even makes any specific references to the events of the Dominion War. Oddly, neither do any of the Trek movies (they mention DS9 only in reference to Worf's background, which coincidentally is exactly as often as DS9 mentions the Enterprise).
I know what you're trying to say, but this is a bad example.
There is no need to mention Voyager on Deep Space 9, because as far as the Alpha Quadrant is concerned, Voyager was destroyed in the badlands.
Deep Space 9 is actually mentioned several times on Voyager. Regarding the Dominion War, Voyager is 70,000 light years away and had no knowledge of the Dominion prior to leaving DS9 in Caretaker
. For what its worth, the war actually IS mentioned when Voyager regains communication with the Alpha Quadrant in Hunters
Anything else would be an example of the Chekhov's Gun principle: there is no need for a character to mention something in a script unless it is important in some way. We never hear much about Deep Space Stations 1-8, but they must exist if we have DS9.