<?php

/**
 * Hide Specific Group Posts From Activity Stream
 **/
add_filter( 'bp_activity_get_where_conditions', 'yzc_hide_specific_group_posts_from_activity_stream' );

function yzc_hide_specific_group_posts_from_activity_stream( $where ) {

    // if is an admin show all activities.
    if ( is_super_admin( bp_loggedin_user_id() && bp_is_group() && bp_is_my_profile() ) ) {
        return $where;
    }

    // List Of Forbidden Groups ID's
    $forbidden_groups = array( 1 );

    // Add Where Statment.
    $where['hide_specific_groups'] = 'a.component = "groups" AND a.item_id NOT IN(' . implode( ',', $forbidden_groups ) . ')';

    return $where;
}