Add exclude option to children macro

I would like to have an option "exclude" for the children macro (and perhaps contentsbylabel as well).

Current situation:

I have some administrative pages in each space, e. g. some includes for the spaces main-page which should not "disturb" the normal users. Current solution is to have a page "Content" and a page "Admin" below the space's homepage and only show the children of "Content". But this has one problem: Most of the time users visit the spaces homepage and press "Add Page" and this will never be shown as "Content". It's hard to administrate such "lost" pages. Therefore I would prefer only to have the "Admin" page as special page but exclude it in the space's homepage like:

I think a comma-separated list would be most convenient as possible arguments to exclude:

Additional Idea:

Perhaps an excplicit "include" might be also desirable (or just extend the page-option to also allow comma-separated lists)... but this should be stated in comments if someone is interested in it. Currently we won't need it