Then trench a line along the posts, drop the chainlink in and cut the rest of the posts to the lowest height post. Backfill and you are done. As long as you are not meeting up with another run no one will ever notice the height difference.
Edit: You can also measure the inside diameter (ID) and go to your local autoparts place to match up a short section of exhaust pipe to fit. Granted it's not as robust as the post itself, but should do the trick.
Edit #2: Like this pipe shown below. Notice the two different diameter at each end of the pipe.
https://www.carid.com/walker/extensi...c7NhoCJYXw_wcB