Filter Activity Stories from rest Endpoint

we are trying to get the Activity stories by rest API using 

api.ashx/v2/stories.xml (or .json)  List Activity Story REST Endpoint  

Filters RestActivityStoryFilters Filters Optional

In the documentation, it not clear how to apply filters 

we need only application-specific content in the JSON data like a blogpost, forum threads,etc .. but not user joined to a group,user1,user2 are friends ......

How can i apply filters only to achieve application-specific content .