Instead of a page range, you might build the workflow differently.
Instead of having 3 pages (copies) - Original, Customer, Store - just submit 1 copy to a workflow. Then use the SPLIT component to make a 'set' for original, another 'set' for customer, another set for 'store'. You will send 'All Pages' to each branch. Then in the branch for customer, apply the store watermark to all pages, then in the store branch, apply the store watermark to all pages. Then JOIN the 3 branches back together. This will put the original pages on top, the customer in the middle, and store copies at the end of the job.
This workflow requires the Advanced Prepress license (which you would need for the Watermark anyways), and I believe the Advanced Automation license (for the Split).
Workflow and samples attached. This workflow requires Core version 6.1.4 to import.
The attached script that you can run in an External Process with the default parameters will add all pages twice to the incoming pdf and write "Watermark i" (where i is the "copy" number") on all pages of the second and third "copy". You need Python installed with PyMuPDF (from cmd as admin run pip install pymupdf). It also assumes there is a C:\Temp\ folder.
Unfortuneately, what you are trying to accomplish is not supported by FFCore. For Watermark page range:
with invoice workflow, the invoice is 3 pages , orgenial , copy for customer , copy for store.
if the invoice 3 pages I need to apply watermark1 for page 2 & watermake2 for page3 .
if the invoice 6 pages , then the watermark1 on page 3-4 , watermark2 on page 5-6.
I need to use $FFwfDoc.pages$ in the placment page range as folow
in watermark1 , ( $FFwfDoc.pages$ /3 + 1 ) - ( $FFwfDoc.pages$ /3 * 2 )
in watermark2 , ( $FFwfDoc.pages$ /3*2 + 1 ) - ( $FFwfDoc.pages$ )
but this dosn't work , I got messge