Social posting all blogs from main site?

I have an MU setup with BP as the main site.
Currently, when someone posts something in their blog, a summary of it shows up in the Activities window.

Each blog owner can run their own social tools but that is not effective as they have to maintain their own social site accounts in order to update them.

I would prefer to have one social posting tool which connects as the main site to say twitter/facebook for example, updating based on activities.

I cannot seem to find something like this. Does anyone have any suggestions? We’ve been struggling with this for weeks now.