Configuring build trigger rules

Hi,

I have a project with a root directory that includes bunch of subprojects. The VCS root is configured to point to that root directory in subversion.

How do I configure the build triggers such that any changes in the root directory itself triggers a new build, but any changes inside any of the subdirectories do not?

Some of my files in the root directory do not have extensions, e.g., settings.xml_sample.

Thanks,
Yaakov.