How to split smarty templates into subfolders?

Question

Smarty

Essence of the question.
In the templates folder there are 3 files
index.tpl footer.tpl header.tpl
I want to put them in a folder
For example, there will be a registration page, I
create a reg folder , I
put these files in it, when called in the site.ru/reg address bar (these index.tpl should work footer.tpl header.tpl)
and so on for each page