I would suggest that you try it manually just to make sure the links will work, and what it takes to make it work.

Remember that to get the link part to work the phone lines have to have that option on the line. Sometimes you can get the link to work and conf in the 3 party but it disconnects when you try the final transfer code. Probably because you need the full option. Telco sometimes calls it by different names. But you need Conference with Transfer.
Once you find out that everything is working then try the fancy codes and routes.

If CON is the opposite of PRO
Then what is the opposite of Progress?