How can I associate a file extension with a content type? I have some files with extension "module" and "inc," which are PHP files. When I try to open them, the list of applications that can open them shows only the application I have set as default application, even though there is another text editor that can open PHP files, and for which I have set the files with those extensions to be highlighted as PHP files are.



If I open the "Get Info" dialog, select another application in "Open With," and then click on "Change All..." what I get is the following.





What I want to obtain is what shown in the following screenshot, which shows the "Open With" menu for another type of file:

 

Is there a way to associate those extensions to the content type used for PHP files?
Alternatively, how can I show, in the list of the applications shown under the "Open With" menu, all the applications that can open PHP files, when Finder doesn't do that already?

I will explain what I want to obtain using a screenshot of RCDefaultApp.



A file using "module" as extension is a PHP file, in my case (it is a Drupal module); what I want is adding that extension to the ones reported for the "public.php-script" UTI.
The Alternative to the Solution mentioned by Gerry is the RCDefaultApp Preference Pane. It's free and let's you set all Application->Content Type, Application->URL connection on your System.

In the "Apps" Pane of RCDefaultApp you can set what file Types a specific Applications Supports when you check "php" with your Editor it will also show in the "Open With" Menu.