Can I query across multiple contexts in one call?

Hi,

I need to query multiple XML files, across multiple directories (or contexts as Xindice calls them). 

For example, in the following directory structure:

            a
            /\
        b        c
    /  /         /   \
d    e        f      g

where a contains b and c
b contains d and e, and
c contains f and g

I would like to have my URI point to b and have Xindice check directories b, d, and e and returns results based on my xpath query. Is there some kind of wildcard that I can use in my URI or a trigger to Xindice telling it to make a resursive search? I would hate to have to make 3 calls when I could make one!

Thanks,
Lisa McCabe