If i understand correctly, you extract a random value from an array that you have extracted with a variable extractor correct? And you will like the same position values from another array. Is it also coming from a variable extractor?

So i assume that the total number of occurrences is the same for both variables right?

Why don't you use a random value which will be used for both variables. For instance, ${var1}_${random} and ${var2}_${random] will get the same position value as soon as the total occurrence is the same.

The only issue with that is you have to know in advance the total number of occurrences. If you don't know it then you can still use that but you will have to create your random value from a Javascript and the max value will be ${var1_MatchNr} which is the total number of occurrences.

You have an example of such Javascript here

You just need to adapti it a bit.

I hope it helps.