How do I install BP Activity copy on sub-site?

Hey. I'm creating an Academy site which is part of my multisite network. I'd like to have the Activity page (which is hosted on the main site) * also * show up on the sub-site. Not like the Activity plug-in, but an actual Activity page which allows 'What's new' and all that.

Also, i'd like to only show posts from beings who are enrolled at the Academy.

It's like this:

intothemythica.com - is the MAIN site, where BP is stored. Normal activity feed page.

academy.intothemythica.com - is where i'm hosting the Academy, and I want the Activity feed there as well, * and * I want it to only show the Activity of students at the Academy.

That way, beings studying courses are only getting the feed from other students studying courses, rather than a regular social feed; though they are part of the same network.

How would this be accomplished?