There are a few ways to modify which stories you receive: first, all stories can be filtered by the various types: blood, friend, enemy, romantic, etc.
Next, each category or story (career, skill, romance, friendship, etc.) has an option to filter which stories you see.
You can also choose individual sims and modify their filter by using the Force Stories option.
In my town of 214 human residents and 109 service sims (yeah, I am running Union Cove hardcore), I set stories to friends, enemies, romantic, blood, and then picked Force Stories to a few select sims I always want to keep an eye on.
Also, realize that filtering out the stories won't keep them from happening (and using computer processing power), it will just keep you from seeing the stories.