If I have a group of fields, can I add another field to the same group from another piklist plugin?

Curious as I’d like to have addons that add data to an existing group.

EX:

piklist('field', array(
    'type' => 'group'
    ,'label' => __('a group test label', 'piklist-demo')
    ,'description' => __('test.', 'piklist-demo')
    ,'field' => 'my_group_field'
    ,'value' => 'none'
    ,'add_more' => true
    ,'fields' => 
    array(
        array(
            'type' => 'datepicker',
            'field' => 'field1_date',
            'label' => 'field1 Date',
            'value' => date('M d, Y', time() + 604800), // set default value
            'options' => array(
                'dateFormat' => 'M d, yy'
            )
	),
      ===============> Can I add a field from another piklist plugin here? <=============
));