how make varaible ( $message ) contain multi odds

i have many value in form php

i want send email and auto replay email via ( mail function )

problem is i want send many odds

i mean the form sent email by content by different possibilities

- send link program 1 only

- send link program 2 only

- send link program 3 only

- send link program 1-2 only

- send link program 1 - 3 only

- send link program 2 -3 only

- send link program 1-2-3


this code php

<?php
$first_name = $_POST['first_name_1'];
  $last_name = $_POST['last_name'];
  $middle_name = $_POST['middle_name'];
  $Street_Address = $_POST['adress1'];
$Email_Address  = $_POST['emailadrres'];
  $program1 = $_POST['inputvalue11'];
  $inputvalue = $_POST['inputvalue1'];
$inputvalue2 = $_POST['inputvalue2'];
  $program2 = $_POST['inputvalue22'];
$inputvalue3 = $_POST['inputvalue3'];
  $program3 = $_POST['inputvalue33'];
$inputvalue4 = $_POST['inputvalue4'];
  $program4 = $_POST['inputvalue44'];
  $inputvalue5 = $_POST['inputvalue5'];
  $program5 = $_POST['inputvalue55'];
$inputvalue6 = $_POST['inputvalue6'];
  $program6 = $_POST['inputvalue66'];

  $toaddress = "myemail@domain";
  $subject = "subject";
  $subject2 = "Confirmation";


  $all=
  "
  First Name: ".$first_name."\r\n
  Last name: ".$last_name."\r\n
  middle name: ".$middle_name."\r\n
  Street Address: ".$Street_Address."\r\n
Email Address: ".$Email_Address."\r\n
  Estimated Total1: ".$inputvalue1."\r\n
  program: ".$program1."\r\n
  
  --------------------------------
  Estimated Total2  : ".$inputvalue2."\r\n
  program2  : ".$program2."\r\n
Estimated Total3  : ".$inputvalue3."\r\n
  program3  : ".$program3."\r\n
Estimated Total4  : ".$inputvalue4."\r\n
  program4  : ".$program4."\r\n
  Estimated Total5  : ".$inputvalue5."\r\n
  program5  : ".$program5."\r\n
Estimated Total6  : ".$inputvalue6."\r\n
  program6  : ".$program6."\r\n
  $mailheaders = "From: $Email_Address\r\n";
  $mailheaders .= "To: myemail@domain.com\r\n";
  $mailheaders .= "MIME-Version: 1.0\n";
  $mailheaders .= "Content-type: text/html; charset=iso-8859-1\n";
  mail("$toaddress", "$subject", "$all", "$mailheaders");  //main mail to admin
  mail("$Email_Address", "$subject2", "$message", "$mailheaders");  // auto replay to user contain link program
  echo("thanks.");
  
  die;
  ?>

HTML:

i want the varaible ( $message ) contain multi odds

thats 7 odds

$message = send link program 1 only

$message = send link program 2 only

$message = send link program 3 only

$message = send link program 1-2 only

$message = send link program 1 - 3 only

$message = send link program 2 -3 only

$message = send link program 1-2-3


i don'y any repeat in this link program in messege