How to protect the blog page with Membership?

Hi,

I’m using Membership in a website with 4 different access levels and my blogpage is not working as I would like.

I have created 4 post categories and have assigned each category to an access levels through Negative Rules; that protects my categories archive and my posts but not the blogpage, where all users can see all the blogpost titles & excerpts (including those assigned to other categories/access levels).

Am I missing something in the Membership settings?

Thanks in advance,

Xènia