I didn't get it. Do you mean, you want to show up all activity of your friends only, on Riverdashboard?

You can try using three column dashboard plugin from the community, it certainly has activity of all members as well (as I recall, riverdashboard had that feature too in the past though).

Vazco is right. You can try Fusion's 3 column riverdashboard which shows a tabbed river offering "All", "Friends", "Mine".

You can even take this one step further by using Brian's MT Activity Tabs plugin which allows users to add extra tabs based on their friends collections or group membership. So far I haven't been able to get this to work on elgg 1.6.1, but on 1.7 it does.

Good luck!