$sql = "SELECT id_module, model, emp_original, emp_exep FROM modules";
               $result = mysql_query($sql) or die ('Ne trouve pas tout les données : '.mysql_error());


	echo "<select name='mod1'>";
		while($row = mysql_fetch_array($result))
		{
		        if(($row['emp_original']) && ($row['emp_exep']=='1')){
		        echo "<option value='".$row['id_module']."'>".$row['model']." </option>\n";
		         }


		}

	echo '</select>'."\n";
	$result2 = mysql_query($sql);
	echo "<select name='mod2'>";
		while($row2 = mysql_fetch_array($result2))
		{
		        if($row2['emp_original']=='2'){
		        echo "<option value='".$row2['id_module']."'>".$row2['model']." </option>\n";
		         }


		}

	echo '</select>'."\n";
	$result3 = mysql_query($sql);
	echo "<select name='mod3'>";
		while($row3 = mysql_fetch_array($result3))
		{
		        if($row3['emp_original']=='3'){
		        echo "<option value='".$row3['id_module']."'>".$row3['model']." </option>\n";
		         }


		}

	echo '</select>'."\n";
	$result4 = mysql_query($sql);
	echo "<select name='mod4'>";
		while($row4 = mysql_fetch_array($result4))
		{
		        if($row4['emp_original']=='4'){
		        echo "<option value='".$row4['id_module']."'>".$row4['model']." </option>\n";
		         }


		}

	echo '</select>'."\n";
	$result5 = mysql_query($sql);
	echo "<select name='mod5'>";
		while($row5 = mysql_fetch_array($result5))
		{
		        if($row5['emp_original']=='5'){
		        echo "<option value='".$row5['id_module']."'>".$row5['model']." </option>\n";
		         }


		}

	echo '</select>'."\n";
	$result6 = mysql_query($sql);
	echo "<select name='mod6'>";
		while($row6 = mysql_fetch_array($result6))
		{
		        if($row6['emp_original']=='6'){
		        echo "<option value='".$row6['id_module']."'>".$row6['model']." </option>\n";
		         }


		}

	echo '</select>'."\n";

<?php

// Requete SQL 
$sql    = "SELECT id_module, model, emp_original, emp_exep FROM modules";
$result = mysql_query($sql);

// Boucle affichant les 5 select 
for ($i = 1; $i <= 5; $i++) {

  echo "<select name='mod".$i."'>";
  
  while($row = mysql_fetch_array($result)) {
  
    if($row['emp_exep']== $i){
    
      echo "<option value='".$row['id_module']."'>".$row['model']." </option>\n";
    }
  }
  
  echo "</select>";
}

?>

Vois du côté de GROUP BY, c'est pratique, du moins, si MySQL le supporte...

for ($i = 1; $i <= 6; $i++) {

  echo "<select name='sty_mod_".$i."'>";
  echo "<option value='choix'>Choix ..</option>\n";
  while($row = mysql_fetch_array($result)) {

    if(($row['emp_original']==$i) || ($row['emp_exep']==$i)){
      echo "<option value='".$row['id_module']."'>".$row['model']." </option>\n";
     }elseif
       ($row['emp_original']==$i){
    	    echo "<option value='".$row['id_module']."'>".$row['model']." </option>\n";
    	    }
  }

  echo '</select>'."\n";

// Boucle affichant les 5 select 
for ($i = 1; $i <= 5; $i++) {

  echo "<select name='mod".$i."'>";
  
           $result = mysql_query("SELECT id_module, model, emp_original, emp_exep FROM modules");
  while($row   = mysql_fetch_array($result)) {
  
    if($row['emp_exep']== $i){
    
      echo "<option value='".$row['id_module']."'>".$row['model']." </option>\n";
    }
  }
  
  echo "</select>";
}

// Boucle affichant les 5 select 
for ($i = 1; $i <= 5; $i++) {

  echo "<select name='mod".$i."'>";
  
           $result = mysql_query("SELECT id_module, model, emp_original, emp_exep FROM modules");
  while($row   = mysql_fetch_array($result)) {
  
    if($row['emp_exep']== $i){
    
      echo "<option value='".$row['id_module']."'>".$row['model']." </option>\n";
    }
  }
  
  echo "</select>";
}

for ($i = 1; $i <= 6; $i++) {

  echo "<select name='mod".$i."'>";

           $result = mysql_query("SELECT id_module, model, emp_original, emp_exep FROM modules");
  while($row = mysql_fetch_array($result)) {

    if(($row['emp_original']==$i) || ($row['emp_exep']==$i)){

      echo "<option value='".$row['id_module']."'>".$row['model']." </option>\n";
    }
  }

  echo "</select>";
}

// on va chercher les enregistrements
$result = mysql_query("SELECT id_module, model, emp_original, emp_exep FROM modules");
// Boucle affichant les 5 select  
for ($i = 1; $i <= 5; $i++) { 
  // remonter au debut des enregistrements
  mysql_data_seek($result, 0);
  echo "<select name='mod".$i."'>"; 
   
  while($row   = mysql_fetch_array($result)) { 
   
    if($row['emp_exep']== $i){ 
     
      echo "<option value='".$row['id_module']."'>".$row['model']." </option>\n"; 
    } 
  } 
   
  echo "</select>"; 
}