What you could do is have the top buttons as they are right now above and outside the form. Have a form beneath that with three fields of options in, all hidden with CSS (in effect, the form is thus hidden).

Add some JavaScript to each button so that, when pressed, it reveals the field relating to that button, and hides the other two. On a second press it might hide that field. You might also need a failsafe to remove any options selected on those fields it is hiding. If you have to do that, you may need to have AutoSubmit OFF, and instead use a submit button.

Hi

If you are using the free Post Grid plugin, because of a change in the Post Grid plugin, you will need to add this code to your child theme’s functions.php file:

add_action('search_filter_filter_next_query', 'set_post_grid_paged');

function set_post_grid_paged(){

        $sfpaged = 1;
        if(isset($_GET['sf_paged'])){
                $sfpaged = intval($_GET['sf_paged']);
                global $paged;
                $paged = $sfpaged;
                set_query_var("paged", $paged);
        }
}

This should fix any pagination issues.

We are working on an integration addon (plugin) just for Post Grid, so that should be available soon.

What I do notice is that you have the same form placed twice in the page. This you cannot do, as they will conflict with each other, even if you are using one for mobile and one for desktop (using CSS to show/hide them).