Compile two queries to one set of results?

That would be nice if you query all three post_types at the same time, using one query, and then manipulating it using php.

Consider this query:

$args = array(
    'post_type' => array( 'pt1', 'pt2', 'pt3' ),
    'meta_key' => BUMP!!!!
);

You can not use an array of meta_keys.

So, I think the only way is to use wp_db object and make your own custom query:

$results = $wpdb->get_results( 
    "
    SELECT ID, post_title 
    FROM $wpdb->posts
    WHERE post_type="pt1" OR post_type="pt2" OR post_type="pt3" 
        AND ...
    "
);

foreach( $results as $result ){
    echo $result->post_title;
    // ...
}

and then use php to separate and show the results.