I want posts of a category to only display on sidebar and not on home

What I want to happen:

1. I want to exclude certain posts from the index page.
2. I then want to display the title of these posts on the sidebar of the index page, enticing readers to click them so they can be read completely.

My Problem:

I’ve managed to do #1, by using techniques mentioned here involving the use of a filter in the functions.php file, excluding posts that fall under a certain category.

However, I cannot do #2 because obviously, I’ve excluded them, so a query_posts for those specific categories I want to display is ‘banned’ from displaying on the index page because of my functions.php.

My Questions:

1. Is there a better way at doing this? I’m open to scrapping the use of above techniques if there is.
2. If not, is there a way I can ‘trick’ my function.php entry into allowing the query_post for those categories to show up on my sidebar?

Many thanks in advance!