Check Checkbox from other Checkbox Listener in list view

I am trying to check one check box from another checkbox listener in a list view. Here is my Code for the Listview Adapter. The Checkbox listener should be able to check a checkbox in any given position in the listview.

 @Override
public View getView(final int position, View convertView, ViewGroup parent) {
    DataSetTasks tasks = getItem(position);
    final int FinalPos = position + 1;
    final int LastPostition = getCount() -1;
    final int FixedLastPosition = LastPostition +1;

    connectionClass = new ConnectionClass();

    final ViewHolder viewHolder;
    if (convertView == null) {
        LayoutInflater inflater = LayoutInflater.from(getContext());
        convertView = inflater.inflate(R.layout.list_layout_orderprogress, parent, false);
        viewHolder = new ViewHolder();

        viewHolder.TaskName = (TextView) convertView.findViewById(R.id.txtTaskName);
        viewHolder.TaskStart = (CheckBox) convertView.findViewById(R.id.cbxStartTask);
        viewHolder.TaskEnd = (CheckBox) convertView.findViewById(R.id.cbxEndTask);

        viewHolder.TaskStart.setTag(position);
        viewHolder.TaskEnd.setTag(position);
        convertView.setTag(viewHolder);
    }else {
        viewHolder = (ViewHolder) convertView.getTag();
    }

    viewHolder.TaskStart.setClickable(position == 0);

    viewHolder.TaskName.setText(tasks.TaskName);

    viewHolder.TaskStart.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {

            @Override
            public void onCheckedChanged(final CompoundButton checkStart, boolean isChecked) {

                if (checkStart.isChecked()){
                    final int TaskID = (Integer) checkStart.getTag() + 1;

                    new AlertDialog.Builder(getContext())
                            .setTitle("Start Task?")
                            .setMessage("Are you sure you want to start this task?")
                            .setCancelable(false)
                            .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
                                public void onClick(DialogInterface dialog, int which) {

                                    String DateTime = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.ENGLISH).format(Calendar.getInstance().getTime());

                                    Toast.makeText(getContext(), "" + TaskID, Toast.LENGTH_SHORT).show();


                                    if (TaskID == 1){
                                        viewHolder.TaskEnd.setChecked(position ==3); // This doesn't want to work
                                    }
                                    else {

                                    }
                                    checkStart.setEnabled(false);
                                }
                            })
                            .setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
                                public void onClick(DialogInterface dialog, int which) {
                                    dialog.cancel();
                                    checkStart.setChecked(false);
                                }
                            })
                            .show();
                }
            }
        }
    );

Any Help Will be extremely appreciated!!!