Specifying which directories to skip during module/themes/registry/... checks

When Drupal searches for module and themes etc. it traverses through all the /sites/* directories.
I installed the Zend Framework module with the Zend framework it's sub-directory. The Zend Framework has a godzillion directories that Drupal goes through when traversing and takes forever to enable or disable modules.

Is there any setting/hook to specify that it should not traverse a specific sub-directory or a regular expression that can specify this?

I know that I can put the framework in some directory outside the /sites/* directory. but still......

Thanks