BuddyPress.org

@javipas – you need to be a little clearer on your setup. In the default setup / theme, the activity stream is a separate page, and not something that shows up on individual blogs / blog pages.

Are you using a custom theme with a custom activity stream, or an activity stream widget in your blogs?

The standard activity stream loop shows activity across your entire BuddyPress installation. If you want to filter the activity steam to just show comments relating to a specific blog, you can write your own custom activity loop:

Take a look at this documentation, in particular filtering on the primary_id to just show posts for a specific blog id: https://codex.buddypress.org/developer-docs/custom-buddypress-loops/the-activity-stream-loop/