NO, you can not search other websites (webservers) directory structure in the way you want to.
Please raed more about how such things can work.
and as the node titles may assume you have to have access to the ressource you want to search.
But even or nonprotected webserver will not give you the directory listing if in each dir is an default file e.g. index.html or deafult.html.
And I've never heard of someone who gave anonymous access to its webspace via ftp.
Have a nice day
All decision is left to your taste