This may not exactly be what you are looking for, but...

I needed to book a ticket (wedding) MCI-DUS (honeymoon) then FRA-IAH (home). This is all within US-Europe. Because CO will allow only one open jaw, we booked MCI-MSP-AMS-DUS then FRA-EWR-IAH-MCI but we booked it with an overnight in Houston and then never took the IAH-MCI flight. Even when I told the res agent that we would not take the flight, she did not care, but the ticket would not "price" unless we did it that way.

Hope you have luck...

BSL