BuddyPress.org

Found it here

bp_core_new_subnav_item( array( ‘name’ => __( ‘Home’, ‘buddypress’ ), ‘slug’ => ‘Home’, ‘parent_url’ => $group_link, ‘parent_slug’ => $bp->groups->slug, ‘screen_function’ => ‘groups_screen_group_home’, ‘position’ => 10, ‘item_css_id’ => ‘home’ ) );