Trying to share a Custom Post from main site to a child site on a multisite network. I am 80% there, with the use of switch_blog I am able to query custom posts on my templates on the child site. I DO NOT want to be duplicating posts for this purpose within the newtwork, I am happy for them all to be sitting and edited on master, whereas the child sites will just read the data. I want to have the same urls, with same content (canonical of course) on both master and sister sites for these custom posts.
One thing remains for this, the single post template - single-items.php This works fine on the main site where it uses some heavy rewrites to display the single custom post on a url of the type: /something/taxonomy1/taxonomy2/taxonomy3/single-post
However, on the child site, as there is no single items in the list (they are all on master) it displays a 404.
Is there a way to hook into the single-post.php template loading so as to force the switch_blog before wordpress goes to check whether the single custom post in question exists and throws a 404?
The part declaring the custom post is sitting in a plugin which is network activated (I thought this would have given me the same custom post on the child site with shared data from master, however when the child site was deployed the custom posts stayed empty).