ASP to search within a range of dates

Hello everyone,
I am writing to you because I am trying to integrate Ajax Search Pro into a project developed on WordPress together with the Advanced Custom Field plugin.

In this project I have to create a type of post that contains different types of data, but in particular in this type of post I have to use many fields (about 8) in the date format (Date Picker in the d/m/Y format). I have grouped all the dates in an ACF Repeater field (a Group field is probably also fine).

I would like to use ASP to search within a range of dates. More precisely, I need to perform a search that allows me to find posts that contain dates within a range (for example: search for dates after 01/10/2020 and before 30/11/2020).

I saw that ASP allows me to do this using “Custom Field” in “Frontend Search Settings”.

I thought that I have to group the dates within a single Database field and I managed to do it by separating them with a comma.

Unfortunately it only works partially. In fact I can do the search but it only works on the dates that are present as the first data in that field, while the dates after the first comma with are taken into consideration in the search.

Hoping to have explained myself correctly, I hope to get some help from you to succeed in the intent.

Below you can see the code (one of the many versions) that I used to group the fields in a single field of the database.

function update_searchable_dates( $post_id ) {
if ( have_rows(‘estremi_cronologici’, $post_id) ) {
$index = 1; // Inizializza l’indice per distinguere i campi

while ( have_rows(‘estremi_cronologici’, $post_id) ) {
the_row();

// Cicla su tutti i sottocampi (data_1, data_2, data_3)
for ($i = 1; $i <= 3; $i++) {
$date = get_sub_field(“data_$i”); // Leggi il sottocampo corrente

if ($date) {
// Salva ogni data in un campo separato con indice progressivo
update_post_meta( $post_id, “_searchable_date_$index”, $date );
error_log(“DEBUG: Salvato _searchable_date_$index -> $date”);
$index++; // Incrementa solo quando trova una data
}
}
}
}
}
add_action(‘acf/save_post’, ‘update_searchable_dates’, 20);