Set the Reply to email addresses to match all tge recipients email addresses (will take recipients of conditional recipients processor)

cf-replyto-all-recipients.php

<?php
add_filter( 'caldera_forms_mailer', function( $mail, $data, $form ) {
    //MAKE SURE TO CHANGE FORM ID
    if( "CF5a5e8452c6f82" == $form[ 'ID' ] ) {
        //If Pro NOT activated
        $mail[ 'replyto' ] = $mail[ 'recipients' ];
        //IF Pro Activated
        //$mail[ 'from' ] = $mail[ 'recipients' ];
    }
    return $mail;
}, 50, 3 );