The functionality to upload a file to an ftp site and select the destination folder based on the file name.

For instance I have X files named [YYYYMMDD]-[ClientID]-EOD.csv and I want to ftp upload each file to a destination folder named /[ClientID]/.

If the client ID is of a fixed length, you could use the {STRING(Substring... function. If not, you could use Regex as follows:

{REGEX(Match|{REGEX(Match|20140322-01234-EOD.csv|(-)(\d+)(-))}|(\d+))}

Of course, you'll need to replace the filename in the statement above with a variable that returns the file name, but I hope this is enough to get you started. Good luck!