Contao nav_default Template, which allows you to switch to the same subpage within a different "category". Simply create a new custom navigation module, select the pages that act as "category roots" and assign this template. You also need to use folder URLs and the page aliases must be the same (except for the first part, i.e. the "category").

nav_switch.html5

<?php global $objPage; ?>

<ul class="<?= $this->level ?>" role="<?= ($this->level == 'level_1') ? 'menubar' : 'menu' ?>">
  <?php foreach ($this->items as $item): ?>
  <?php

// get the current page's alias and remove its first part
$arrAlias = explode('/', $objPage->alias);
array_shift($arrAlias);

// create target alias for switch
$strTarget = $item['alias'] . ($arrAliases? '/' . implode('/', $arrAliases) : '');  
$objTarget = \PageModel::findByAlias($strTarget);

// check if target exists
if ($objTarget === null)
    continue;

// create new href
$item['href'] = \Controller::generateFrontendUrl($objTarget->row());

    ?>
    <?php if ($item['isActive'] || in_array('trail', explode(' ', $item['class']))): ?>
      <li class="<?= $item['class'] ?>"><span class="<?= $item['class'] ?>" role="menuitem"<?php if (!empty($item['subitems'])): ?> aria-haspopup="true"<?php endif; ?>><?= $item['link'] ?></span></li>
    <?php else: ?>
      <li<?php if ($item['class']): ?> class="<?= $item['class'] ?>"<?php endif; ?>><a href="<?= $item['href'] ?>" title="<?= $item['pageTitle'] ?: $item['title'] ?>"<?php if ($item['class']): ?> class="<?= $item['class'] ?>"<?php endif; ?><?php if ($item['accesskey'] != ''): ?> accesskey="<?= $item['accesskey'] ?>"<?php endif; ?><?php if ($item['tabindex']): ?> tabindex="<?= $item['tabindex'] ?>"<?php endif; ?><?php if ($item['nofollow']): ?> rel="nofollow"<?php endif; ?><?= $item['target'] ?> role="menuitem"<?php if (!empty($item['subitems'])): ?> aria-haspopup="true"<?php endif; ?>><?= $item['link'] ?></a></li>
    <?php endif; ?>
  <?php endforeach; ?>
</ul>