BuddyPress.org

There is only one instance of BuddyPress in one WP multisite installation.

You’d need two plugins to have have separate instances of BuddyPress in a multisite install, one plugin to create multiple WP networks and another plugin to enable distinct and separate BuddyPress instance in each network http://wpmututorials.com/news/new-features/multiple-buddypress-social-networks/