That’s a lot of cat to skin…
From a Windows App? Do you have control over the Windows app? Since it’s third party, I’m going to guess not. How does the program intend to initiate such a transaction? What choices are there in the system to make this thing start our thing?
If you can send it to an arbitrary web page, you could use ARI.
If you can send a file to the server, you could use a call file.
If you have to set up a receiver, you could do one or the other.
The tricky part after that is the repeating until an event. Does the program terminate the event? How? Do you need to write an app on the phone server to terminate the event?
Lots of cat to skin here.