C:\>xcopy /?
...
/EXCLUDE:file1[+file2][+file3]...
Specifies a list of files containing strings. Each string
should be in a separate line in the files. When any of the
strings match any part of the absolute path of the file to be
copied, that file will be excluded from being copied. For
example, specifying a string like \obj\ or .obj will exclude
all files underneath the directory obj or all files with the
.obj extension respectively.
Você precisa colocar "Source Code" em um arquivo e especificar esse arquivo na linha de comando.