Hello Alessandro

You can only include/exclude which items are going to be displayed in the showcase slider.

To achieve what you want is actually not difficult but you need to do some coding

you need to create copies of the showcase-page.php rename them and then change the name of the template (the first lines in the file header)

then you need to modify 

$grenada_args = array(
'post_type' => 'grenada_portfolio',
'paged' => $grenada_paged,
'posts_per_page' => 1000,
);

so that will onclude only certain items

https://codex.wordpress.org/Class_Reference/WP_Query#Post_.26_Page_Parameters

see post__in or post_name__in parameters

Hi Alessandro,

for portfolio category pages you have a special url

http://clapat.ro/themes/grenada-wordpress/portfolio_category/design/

note the taxonomy 'portfolio_category' and the slug 'design'

Coming back to your question, this is how the query arguments would look like:

$grenada_args = array(
'post_type' => 'grenada_portfolio',
'paged' => $grenada_paged,
'posts_per_page' => 1000,
'tax_query' => array(
        array(
            'taxonomy' => 'portfolio_category',
            'field'    => 'slug',
            'terms'    => 'design',
        ),
);

Yes, probably, but you create the page and the page url is different than the page template. What you need to make sure is that you have assigned the page template correctly in page options.

Plz double check.

Then you need to check the code to see if there are additional errors. if everything fails sens us wp admin access.

Thank you Alessandro, appreciate it as well.