Using nested shortcodes across different post types

Hello, I am trying a new way to layout my content but I have hit a snag.
The site I’m working on is sort of an homage to an old local newspaper, with several “articles”.
Because of this I have added a post type “articles”, which will be referenced by an article shortcode with the specific article id.
[article id=#]
will go into another custom post type “columns”, which would be entered into a PAGE type post like so:
[column id=#]

So it seems to me that this would be shortcode nesting, even though they aren’t on the same “page” in the backend.

Here are my shortcode functions:

function art_display_shortcode_fn ( $atts ) {	// allows an admin to enter articles into columns via shortcode like so: [article id=#]  where id is the post id number

	extract(shortcode_atts(array('id' => ''), $atts));

	$article_post_id = $id;

	$post_object = get_post( $article_post_id );

	echo '<div class="articlecontainer">';

	 echo '<h2 class="list_title">'.$post_object->post_title,'</h2></a>';

 echo '<p class="list_excerpt">'.$post_object->post_content,'</p>';

 }

 	add_shortcode( 'article', 'art_display_shortcode_fn' );

function column_display_shortcode_fn ( $atts, $content = null ) {	// allows an admin to enter columns into posts and pages via shortcode like so: [column id=#]  where id is the post id number

	extract(shortcode_atts(array('id' => '', 'article_post_id' => ''), $atts));

	$post_id = $id;

	$post_object = get_post( $post_id );

return '<div class="column">' . do_shortcode($content) . '</div>';

 }

 	add_shortcode( 'column', 'column_display_shortcode_fn' );

When I try it with this I get the <div class="column"> to show up on the front-end, but it is not containing the articles as I believe it should.