Get list of Meta values from ACF Repeater-Field

Hi

We run an Eventsite for a Concert-Location. We do that with a Custom-Post-Type “events” and the date-function from ACF. That works fine.

We write a new Post (Event) and in there whe have a ACF Repeater-Field “artists” with the field “artistname” playing on this event.

Now we want a new page with a list of all Artists (artistname) played at our club in the past. That list should display all Artisnames alphabetically.

So the query should find
1. past events – that works
2. the repeater-field “artists” and give a list of artistnames.

For Example
Event one with Bandname A, Bandname Z
Event two with Bandname B and Bandname X

On the new Site we want a list like
Bandname A
Bandname B
Bandname X
Bandname Z

My query_post so far

<?php
$today = date('Ymd');
$args = array(
   'post_type' => 'events',
   'meta_key'  => 'date',
   'meta_value' => $today,
   'meta_compare' => '<',
   'posts_per_page' => '-1',

   'meta_query' => array(
        array(
            'meta_key' => 'artistname',
 	    'orderby' => 'meta_value',
 	    'order' => 'ASC',
        )
    )
);
query_posts( $args );
?>