How can i send a nested List response in XML using Custom Service

Hi All,

I am trying to achieve the below XML response where when we pass the Customer ID and TransDate as input, system should send the Sales ID's and the Invoice ID's which are related to the input parameters.

Service Request:

<?xml version="1.0"?>

<LoginResponse>

    <CustId>1234ab5678</CustId>

    <Date>10/10/2018</Date>

</LoginResponse>

Expected Service Response:

<?xml version="1.0"?>

<CustomerInfoResponse>

   <CustId>1234ab5678</CustId>

   <Date>10/10/2018</Date>

   <SalesOrder>

       <SalesId>800000XXX1</SalesId>

       <SaleTransDate>10/10/2018</SaleTransDate>

       <Address>123 MG Road, 219435</Address>

       <Invoice>

           <InvoiceNumber>914200XXX1</InvoiceNumber>

           <InvoiceNumber>914200XXX2</InvoiceNumber>

           <InvoiceNumber>914200XXX3</InvoiceNumber>

       </Invoice>

   </SalesOrder>

   <SalesOrder>

       <SalesId>800000XXX2</SalesId>

       <SaleTransDate>10/10/2018</SaleTransDate>

       <Address>456 MG Road, 219445,</Address>

       <Invoice>

           <InvoiceNumber>914200XXX4</InvoiceNumber>

           <InvoiceNumber>914200XXX5</InvoiceNumber>

           <InvoiceNumber>914200XXX6</InvoiceNumber>

       </Invoice>

   </SalesOrder>

   <SalesOrder>

       <SalesId>800000XXX3</SalesId>

       <SaleTransDate>10/10/2018</SaleTransDate>

       <Address>456 MG Road, 219445,</Address>

       <Invoice>

           <InvoiceNumber>914200XXX7</InvoiceNumber>

           <InvoiceNumber>914200XXX8</InvoiceNumber>

           <InvoiceNumber>914200XXX9</InvoiceNumber>

       </Invoice>

   </SalesOrder>  

</CustomerInfoResponse>

  Request you all to help me to understand, how can i send the list of both the SalesOrder and the Invoive.