I think i have to do a user query like this:
– getting all users
– check if the user IDs are equal to an ID in the custom field entrys added to the page
– than drop the ones whos ID is not in
EDIT: this is the solution. So simple that I could not get it 😀
<?php
//get the users
$ids = get_field('personen_intern', false, false);
//include them in the query
$args = array(
'include' => $ids,
);
?>