The foreing carriers I know don't have jumpseat coordinators, but they still allow other carriers pilots to ride in the jumpseat if there is no room in the pax cabin.
One time I had a non-rev ticket to fly from SJU to MIA on AA and the flight was full, so I asked the gate agent for a jumpseat and she said that it wasn't possible because the plane was overweight. I asked her to talk to the captain but she said that the captain had nothing to say about it. So, I had to wait for the next available flight.