[Typo3] Subpage templates - how to use only one??

[Joonas Savolainen]

Hi all,

I needed a different layout for the frontpage and the subpages, so I
created the template for the frontpage, and then use an "extension
template" for every single subpage... the extension template loads a
different html-template and creates a sub-navigation etc... 

The problem is, that I have to put the extension template manually for
each subpage (more than 10 of them), and when I need to change something
in the template, I have to edit every single subpage's template setup,
which contain 139 lines now each..

Is this even a good way to do this all?? Does it load the server heavily
or something..? How could I use the same extension template for every
subpage? :P

Thanks for any help! :/

Joonas S.