Update Sync?

This may be answered elsewhere, but I tried searching both the help files and the forums, maybe I missed it.

Is there a way to Update, Copy Newer, or Copy Missing in a sync operation?

I have a situation where I have multiple source folders that will have files added to them regularly:

Folder A Folder B Folder C
File A1 File B1 File C1
File A2 File B2 File C2
File A3 File B3 File C3
... ... ...
File An File Bn File Cn

I need to copy all the files from these locations into one folder, but only the ones I'm missing. Because I will work with my copy of these files and update them on a regular basis but the source files won't change, only have new files added.

I'm using version 3.0.4

All the sync functions seem to want to either overwrite my files that I've updated with the older originals and/or copy my files into the source directory which I don't want to change at all and/or delete files that are from the other 2 folders.

Thanks for any help you can offer.