Automatic Values - Simple automatic numbering with VBS

Hello All,

All new incoming orders come without tracking number in the order.

We generate Tracking Number with Automatic Values  - Simple automatic numbering without any problem and upload this orders to M-Files., but today we received new request,

Customer provide to vendor span of tracking numbers for ex between 90000-100000.

From now some orders will be come with this Tracking Number in the order.

They would like continue generate Tracking Numbers with Automatic Value but if incoming order already have Tracking number just add value to Property definition.

I will very appreciate for any ideas