Not show older posts on index.html

I maintain a dutch site https://www.hetleegeland.nl On it I show news items, wich I publish as blog entries and other theme-oriented items, for which I use the entry technique as well. These thematic entries don’t have to show on the index.html though (they’re not news). I gave them an older date, so they are pushed “backwards”. How can I make them to stay published (under several categories/thema’s) but not published on the index.html, and especially de-publish them from the “older articles” pages? Is there a “not publish before date” plugin I can use on index.html?
P.S. the sticky article on top will need to be resolved as well, I have the plugin, so don’t bother. Thanks.