Hi
This wouldn't be a feature of this bridge. Usually, XF is the master. Instead, let me write something for free for you and others to download.
Please explain the structure of your site. Are both WordPress and XenForo currently installed on the same server, same domain? Or is the site currently WP and you are wanting to migrate to XF? In which case, how many posts are in WP and do you want those migrated, too?
This could be written as a WordPress plugin or as a XenForo addon.
From the WordPress installation, get the users.
PHP:
get_users( array $args = array() )
From the XenForo side, insert users into the proper table. This code is from the XenForo importer.
PHP:
$newId = $user->insert($oldId, $db);
foreach ($this->tables AS $type => $table)
{
if ($type == 'user')
{
continue;
}
$table->set('user_id', $newId);
$table->insert(false, $db);
}