Hey Rama -
No, not directly "out of the box", anyway. You could still do this, but it would require some extra work on your part outside of Tableau.
Using a Tableau URL Action, you'd build up a query string like http://mywebservice?Parameter1=<TableauField>&Parameter2=<AnotherTableauField>
Your web service would grab the values in Parameter1 and Parameter2 and then "do work". That work would be to grab / filter / merge data however you need to, and drop the results in a table that Tableau is ALREADY connected to.
Hope this helps.