Below is an example of how to restrict a Google search to a subdirectory on the Library Web Server. Use View / Source to see the code.
You need to change the line that contains:
...type=hidden name=hq value="inurl:www.library.yale.edu/beinecke"...
to point to your own sub-directory.
To see another example on a Library site, see the Science Libraries Search page:
Note that it is not possible at this time to 'wrap' the results in a Library-specific header and footer. That functionality did not exist with our old search engine (ht/dig) either but we hope that it will be possible with Google in the future.