I want to exclude sub pages from my main nav, but automatically include them on a side block auto nav.

Here is my example
Main Nav

Page 1
Page 2 - Page 2 has subpages, but they should not show up on main nav

Page 2 - on left sidebar show all sub pages with autonav

so on Page 2 on the left sidebar should be

sub-page1
sub-page 2

etc.

Does anyone know of some way to do this? I can use exclude subpages from nav - but that will also exclude them from the left sidebar on the parent page.