groups_send_invites( array $args = array() )

function groups_send_invites( $user_id, $group_id ) {

	if ( empty( $user_id ) )
		$user_id = bp_loggedin_user_id();

	// Send friend invites.
	$invited_users = groups_get_invites_for_group( $user_id, $group_id );
	$group = groups_get_group( $group_id );

	for ( $i = 0, $count = count( $invited_users ); $i < $count; ++$i ) {
		$member = new BP_Groups_Member( $invited_users[$i], $group_id );

		// Skip if we've already sent an invite to this user.
		if ( $member->invite_sent ) {
			continue;
		}

		// Send the actual invite.
		groups_notification_group_invites( $group, $member, $user_id );

		$member->invite_sent = 1;
		$member->save();
	}

	/**
	 * Fires after the sending of invites for a group.
	 *
	 * @since BuddyPress 1.0.0
	 * @since BuddyPress 2.5.0 Added $user_id to passed parameters.
	 *
	 * @param int   $group_id      ID of the group who's being invited to.
	 * @param array $invited_users Array of users being invited to the group.
	 * @param int   $user_id       ID of the inviting user.
	 */
	do_action( 'groups_send_invites', $group_id, $invited_users, $user_id );
}