So, the problem is quite simple, not sure the answer will be.
I'm designing a website which will have different sections, more or less separated from each other.
I'm using templates with custom headers to style the pages differently. I'm using a custom query in the main loop to exclude posts from some categories from the front page. I'm using a custom loop to get these excluded categories to show on another section of my website.
So far so good... until I click a post. Which, of course, is calling single.php, and I can't style it differently (I would need a whole different header, etc.). What I'd like to do is to have my custom loop (right now, loop-level3.php) call a single-level3.php file when somebody clicks on a post belonging in this section.
I've read about custom post types, it doesn't really seem the way to go. I don't need anything specific about the posts, like special features and such, I just need my loop-level3.php to call a special single-level3.php page.
Is something like that possible? I browsed through the codex and forums, I found lost of topics where people want to change a few minor things (I've done a whole website where each category is styled differently, each post is also styled according to the category, but it didn't involve a new header file), but I haven't found anything like what I need.
Any advice on how to proceed?