Works great. Thanks Martin!

Use a file mask:

See https://winscp.net/eng/docs/scriptcommand_synchronize#filemask

I run a phpBB board that I'd like to synchronize locally, including the /files subdirectory which stores user's uploaded attachments. But the /cache and /store subdirectory are dynamically populated by the board itself; there's no need to preserve their contents. Because there are easily a dozen subdirectories in the root directory, I'd like to synchronize the root while excluding these two subdirs, instead of calling out each individual subdirectory for synchronization. Is there a way to do that?