Hi,
There is no option to do that.
With the next version of hikaShop (the 3.0 which should be out next month), you'll be able to edit the file "listing" of the view "product" via the menu Display>Views and add the code below at the top and it will work:
<?php if($_REQUEST['ctrl']=='product' && !$this->module && empty($this->filter_set)){
$app = JFactory::getApplication();
$app->redirect('http://mywebsite.com/link/to/my/categories/listing');
}
?>
with the current version the variable $this->filter_set is not yet available in that view so the code won't work.