Creating a working constructed list using unverified perl

I am having troubles with a constructed lists. I have three "variables"
UserID, Car and Color. Each user can own 1 up to 3 cars as in the table below.

UserID Car1 Color1 Car2 Color2 Car3 Color3
Susan Ferrari Red Opel Blue
Mark Nissan Black
John Subaru Red Lamborghini Orange Maserati Grey

I have created three lists:

The first one (CarList) has [%Car1%], [%Car2%] and [%Car3%] as entries.

The second one (ColorList) has [%Color1%], [%Color2%] and [%Color3%] as entries.

The third one "CarColorList" has
"[%Car1%] ; <i>[%Color1%]</i>" ;
"[%Car2%] ; <i>[%Color2%]</i>";
"[%Car3%] ; <i>[%Color3%]</i>"
as entries.

I would like to create a construct list whose parent list is "CarColorList" which shows 1 car if the user has one car, 2 cars if he has 2 cars and 3 cars if 3 cars are owned.

As an example, if the user is Mark, only "[%Car1%];<i>[%Color1%]</i>" should appear, while if the owner is John "[%Car1%];<i>[%Color1%]</i> [%Car2%];<i>[%Color2%]</i> and [%Car3%];<i>[%Color3%]</i> should appear.

I have wrote the following unverified pearl code

 Begin Unverified Perl

my %Values = ();
my $ i = 0;

for($i = 1; $i <= LISTLENGTH("CarColorList"); $i++)
{
if(!exists $Values{(LISTLABEL(" CarColorList  ", $i))} && (LISTLABEL("CarColorList", $i) ne ";"))
{
$Values{uc(LISTLABEL("CarList1", $i))} eq LISTLABEL("CarColorList", $i);
      ADD(" CarColorList", $i);
}
}

End Unverified