Merging (mix-down) audio files

When producing our podcast we record each participant into a separate audio file. These files then go off to an editor who levels / edits / cleans-up.
However, whilst this is going on, we take a rough mix-down and share it in order to write show notes etc.
I'd love to craft a rule that does this by dropping a load of files into a folder. Does anyone know how?
I can see a way to do it if I wanted to append the 3 files together, but for merging my Googling came-up empty.
Any help much appreciated,
Ben
However, whilst this is going on, we take a rough mix-down and share it in order to write show notes etc.
I'd love to craft a rule that does this by dropping a load of files into a folder. Does anyone know how?
I can see a way to do it if I wanted to append the 3 files together, but for merging my Googling came-up empty.
Any help much appreciated,
Ben