Buddypress and Multisite Privacy issue

Ok, the way buddypress works is that it does a check to see if the blog is public. If it's public, it will display the activity in the network.

174 $is_blog_public = apply_filters( 'bp_is_blog_public', (int)get_blog_option( $blog_id, 'blog_public' ) );

I want to change this filter to the one in multisite privacy plugin that reads "Visitors must have a login - anyone that is a registered user of Innovate UH can gain access."

Any ideas on how to go about this? I want to change it to filter out only blogs that fall into these three categories: