[TYPO3] different colPos_list for page and subpages

[Claudio]

Hi all,
I have a site whose pages have two different layouts: basically the home
page plus some subpages have 3 columns, while most of the pages are
single-column. I'd like to make only the needed columns available to BE
users. I know about the mod.SHARED.colPos_list, but I need to set a
different value for the home page (root of my tree):

mod.SHARED.colPos_list=0,1,2

and for the subpages:

mod.SHARED.colPos_list=0

Is this possible at all, without setting the value on each subpage?
Thanks in advance

Claudio