Filter records based on device id of client when syncing

Hi

I am trying to filter records from the hosted file to client file while syncing based on which client device id is syncing. So I am trying to do this in the prepare payload for client script in the Hosted File database.

This is where I need to add my business rule, but am not sure how to manipulate the dyn sql variable there to include this business rule. I would like to check if the sync table is a particular table and if a particular client device is doing this sync and if that particular sync table has a field set to some value then that record should be pulled down. Otherwise not. How exactly would I go about doing this? I have not seen any example manipulating dyn sql on this forum... and I need this for my conditional down syncing ......