multiple tables

Hi

I am trying to create an experiment in which people need to rate different texts (URL names).
However, I want to have different lists of URLs for every 3 participants.
so I created a random variable to set the subject number and used If then statement to select the list. 



table trainconditions
"number2 location" "google.com" 0 2 1
"number3 location" "google.com" 0 2 1
"number4 location" "face2book.com" 0 2 1
"number2 location" "facebookert.com" 0 1 1


table2 trainconditions2
"number2 location" "youtube.com" 0 2 2
"number3 location" "youtubepoi.com" 0 2 2
"number4 location" "gmogle.com" 0 2 2
"number2 location" "gm34rogle.com" 0 1 2

task comparison
set $Ra random 1 30
keys 1 2 3 4 5
  if $Ra <= 3
    table trainconditions
    fi
     table2 trainconditions2
     delay 500
      clear 1
show background 0 0 0 ##creates a grey background
show text @2 @4 0
readkey @4 0
rate option pos 0 100
rate option labels unreal real
rate 10000 5
clear 2
save @1 STATUS BLOCKNAME RATE RATE_RT RATE_STATUS

I thought about creating many different tables (trable set 1; table set 2 etc). however I am getting an error saying that table has been already used.

Does anyone have a creative idea on how to solve this?