The tar
format does not allow adressing a file (or a directory) directly - this is due to the fact, that tape archives were ment to be sequentially read from a backup medium.
What you can of course do, is stop the process after the relevant parts have been extracted. You would do something along the lines of
curl -o - 'http://your/url' | tar -xvz your_filter
This will download the file starting from the beginning and extract the relevant parts, once you have everything you need, you can stop the process to avoid downloading the rest.
Depending on what sort of access you have to the source server, you might even do better: Do you have PHP without save mode? If yes you can extract what you need via shell_exec
and friends.