I don't believe CNN gives stations that power to embargo something in another market just because their parent company owns another station there. I don't think I've ever seen that happen. Typically, something is only embargoed for other stations in the same market or if it includes video that's restricted for one reason or another.
In one place where I worked, our sister station one market over threw a big stink at us because one of their competitors (a Sinclair station) ran one of our packages that CNN picked up. The reporter had a stand-up in it while wearing our jacket and mic flag with a logo that's nearly identical to our sister station's. They somehow thought there was something wrong going on, but since it's two different markets, there wasn't any embargo on it, so it was fine for the Sinclair station to run it even though our sister station had access to all of our content internally. Probably a dumb move on the Sinclair station's part to run a package that looked like it came from their competitor, but whatever. Or at the very least, they could have edited out her standup.
That's the double-edged sword with being a CNN affiliate. It's great because Newsource has tons of video, including lots of packages, but if there's more than one CNN affiliate in a market, then competing newscasts can end up running a lot of the same content if you're not careful or get in the habit of only checking CNN for wire content.