Can I have a body apply to a different page than the current content type?
I'm not totally clear on what you are asking, but I will try to help anyway (and maybe with more clarification I can help further)).

It sounds like you have a gallery content type. Do you need these gallery images for anything else? Because it also sounds like you want an image to show up on the news article page. If that is the case, why not just have fields for the images, caption, and link in the news article content type? That way, when the person goes to edit the news article, everything is write there - both the fields related to the news article itself as well as the fields related to the gallery ones. I feel like this would make more sense to the person editing it anyway.

And then if you still need a separate gallery or something using the images that have been added, you can still use the images in the news article content type to make a separate view.