GPS Forwarding same vehicle ID on two devices


We are using GPS Forwarding, and it works great. We noticed a few days ago, that we have two different devices with the same last 4 letters (Vehicle ID).
In our system, we are parsing the location, and according to the Vehicle ID, we are assigning the location to the relevant vehicle.
Now that we have this issue, is there an option to send the last 6 letters of the decisive serial, how can we distinguish between the locations of these two devices?