Trying to figure out if it's possible so I have time to post the next update.  Any help is appreciated

Top of the thread (above the first entry) is a list of commands for a thread, you can lock or unlock a thread from there. I have used it as such at least a couple of times over the years.
Look under "Edit Thread" for what you need.

I recommend you let your players know you locked it on purpose to avoid getting a lot of posts telling you that it is locked.