This can be done by :
– 1st : pusching the selected data to the ajax request. For this you should use
select2_ajax_data javascript filter and add a new element in the ajaxData array using the ACF JS API.
Let say ajaxData.myparameter = getField(yourselectbox)
– 2nd : Once this is ok, use the acf/field/post_object/query on php side.
This filter is used to retrieve information and add them to the query.
For this get $_POST[myparameter] ?? get_field(yourselectbox).
$_POST : used to get ajax value from JS.
get_field() : used when you update the page to used the current saved value for yourselectbox.
Then you update the query to get the value for the other fields.
