Template Manager by WordPress Monsters

You can create templates (layout) for your pages to add some blocks of content before/after general content.

Also you can assign your template to custom post type(archive or single), taxonomies, 404 and search results pages, this options can be found in Templates->Settings menu in admin console.

You should use

[wpm-template-content]

shortcode in this templates to separate content.

Watch how to use Template Manager plugin in this cute short video: