Partha, Hi

Yep of course there is.  A little bit complicated but i think i can explain
it step by step.

The problem you have to overcome is to get the form to check the value on
the form againt a column in an XML document, find a match and then report
back the corresponding value of a different column in the XML.  On a rule
however you have only 2 of these steps so what you use is the filter on the
data connection.

Have another invisible textbox on the form thats value is from the XML
source filtered by the value entered in your textbox, this will give you the
functionality you need and your rule just says if textbox1 is not blank set
it's value equal to the invisible textbox.

I hope this achives what you want.

Cheers Adam