copying a file in a specific subfolder to another folder

Hello!
I have tried searching for the answer to this on the forums but have had no luck.
I would like to set up a rule that finds any waveform audio inside a specifically named subfolder (mixdown) and copy it to an "all mixdown" folder.
So for instance, I have music projects sorted in folders as follows: Music sessions/artist name/all project contents including a mixdown folder.
when I create a file that goes into that mixdown folder I want it to be copied to another folder.
Any help would be greatly appreciated!
I have tried searching for the answer to this on the forums but have had no luck.
I would like to set up a rule that finds any waveform audio inside a specifically named subfolder (mixdown) and copy it to an "all mixdown" folder.
So for instance, I have music projects sorted in folders as follows: Music sessions/artist name/all project contents including a mixdown folder.
when I create a file that goes into that mixdown folder I want it to be copied to another folder.
Any help would be greatly appreciated!