You may want to keep up with the Neighborhood Link's Blog.
There are directions there right now that tell you how to get rid of all the Topic lines from other neighborhoods in your Discussion Forum. This is an individual thing so if you don't want to see them you need to go to the blog, find the one called "New Preferences in User Profiles" and follow the directions. Basically it says " The easiest way to make this change is to login, go to your neighborhood discussion forum, and then click your user name in the upper left corner of your browser window." Then at the bottom of the page there will be a drop down window that says standard and can be changed to restriced if you only want to see the topic lines from your own subdivision/group.