Is it Real to make dynamic List

Dear Anaplanners, 

I have a modeling issue. We have an "Agreement Register" in anaplan, it has the structure you can see in attached photo:

The values for each agreement are being changed every month. Also every month we need to Export "Unique code + Value" to other system, and each line there becomes enrighed with additional unique code. For example:

So the next step I should Import IDs to match "Unique codes" in Anaplan. What is the best way to arrange it.

As you see it's not good idea to create List from "Unique code", because it should be made for each month. 

You may advise me to create new List each month and delete when required month Import is finished.

Is it possible to make it in other way?

Thank you.