How to extract string value and construct contact string in Windows Batch

Hi
Could you help with below please.

Scenario:
- In Windows batch, would like to check a folder with specific file pattern e.g *.sif. We might find 1 or more files. Files are in sif extension but it just a text file in xml style. (not binary)

- Look for string "PROCESS_NAME" and get the value of of it. E.g PROCESS_NAME="TEST Workflow 1"

- Loop through all files in the directory and get all values. E.g. if we find "TEST Workflow 1" and "TEST Workflow 2" etc etc.

- Variable should be set like below.
e.g workflow_list='TEST Workflow 1','TEST Workflow 2','TEST Workflow 3'

If it is easy in powershell, we can do that, but is it easy to bring the value back to batch variable please

Have attached two sample files.

Thanks in advance :)
wf_nxg_application_error_handler_wor.txt
wf_nxg_publish_error_republish_batch.txt