You can have any page template in use within any page of the system. You only need to tell the software what template to use on a specific page. Within a template set are the templates used in that template set and what pages each template is attached to in the system.
Highlights of template attachment…
Look to find the pages within the system that allow template attachments to them here in the admin tool:
DESIGN > PAGE ATTACHMENT
The following screenshot shows that page in the admin tool:
Within that screenshot you'll see this:
Once you click edit in the above illustrated admin tool you'll be directed to a page that looks like:
Within that screenshot you'll see these sections:
Once you are done setting your page template click the save button to save your choices.