This would require some custom programming as we do not have integration with any of the multi-lingual plugins to do it automatically.
For example, if you are using the Custom Fields extension and each version of the site has it’s own form scheme then you could use something like this to filter the ads by the form scheme used (this should be equal to filtering by language used when posting)
add_filter( "adverts_list_query", "filter_by_form_scheme", 10, 2 );
function filter_by_form_scheme( $args, $params ) {
$page_to_fs = array(
100 => "scheme_name_1",
200 => "scheme_name_2"
);
if( ! function_exists( "wpadverts_custom_fields_get_form_scheme" ) ) {
return $args;
}
if( isset( $params["add_form_scheme"] ) ) {
if( ! is_array( $args["meta_query"] ) ) {
$args["meta_query"] = array();
}
$scheme = wpadverts_custom_fields_get_form_scheme( "add", $page_to_fs[get_the_ID()] );
$args["meta_query"][] = array(
"key" => "_wpacf_form_scheme_id",
"value" => $scheme->ID
);
}
return $args;
}
where 100 is the ID of the page with the classifieds list block and scheme_name_1 is the name of the form scheme (similarly with 200 and shceme_name_2)