Please don't do this. Which thread should we respond to? Should we all be expected to read both threads to see what others have said in response?
In a more general case, you could have someone going to a lot of trouble to research a problem for you and write a long response in one thread, without being aware that someone else has already made a similar effort on the other thread. This is one reason why crossposting has been frowned upon on message boards since long before the World Wide Web.
In future, if you really feel you must make the post in one thread and take responses there, then just post a link in the other thread.