Join multiple Pdf files if name matches

I have set up a workflow read all the pdf files in a specific folder.
Set up a condition - if Name 1 contains NewName, join all pdf files.
However, it returns nil result. none of the file were joined.
Name of the invoices : Invoice 1.pdf ;Invoice 2.pdf; Invoice 3.pdf
workflow screenshot as per below.

Greatly appreciated if anyone can help.

Hi Do you get it work ? Im also looking for the same