Blueprint select field queries for more than one page

The CMS Questions
3

The best way to go about that would be to use dynamic options via a json API: https://getkirby.com/docs/cheatsheet/panel-fields/select

E.g. json.php template

<?php
header('Content-type: application/json; charset=utf-8');

$collection1 = page('projects')->children();
$collection2 = page('products')->children();
$newCollection = $collection1->merge($collection2);

foreach($newCollection as $p) {
	$json[(string)$p->uid()] = (string)$p->title();
}

echo json_encode($json);

?>

Make sure that the children of the two main pages do not have the same uid.