hierarchial build.xml

[Viraj Purang]

HI,
   Is it possible to have the ant pick up the build.xml  at a lower level by
itself.
I have a pretty unruly set of developers, who want to have the freedom to
just add 
their valid build.xml file with the new code / directories they are checking
in .

It would be really nice if the upper most level build.xml file can pick this

file automatically, 
rather than me having to specify the same as a part of the ANT tag.

Thanks and Regards,
Viraj Purang