Ok, I did it another way.
First, get all the terms for the taxonomy.
If the term is equal to the value requested, put it into an array
Then do the tax_query with this array.
Final
$argsc = array(
'order' => 'ASC',
'hide_empty' => true,
'fields' => 'all',
);
$termsc = get_terms("cities", $argsc);
$cities_array = array( );
foreach ( $termsc as $cterm ) {
//Get country Customf ield for that term
$thecountry = get_field( 'country', $cterm );
if($country == $thecountry){
//if custom field == variable from select/search put in array
array_push($cities_array,$cterm->name);
}else{
//do nothing
}
}
ksort( $cities_array);//just sorting
$args = array(
// Arguments for your query.
'posts_per_page' => '12',
'post_type' => 'ARTICLES',
'orderby' => 'date',
'order' => ASC,
'tax_query' => array(
array(
'taxonomy' => 'cities',
'field' => 'slug',
'terms' => $cities_array,
),
),
'paged' => $paged,
);