[mod_python] How to have a form submit to two different servlets with _call_

I'm using the _call functionality significantly.
Depending on the button the user preses, I need to
submit the form to two different servlets.

I'm ujsing the onclick functionality of the submit tag
on the form:

<input type=submit 
name="_call_do_some_function()" 
onClick="document.mainform.action='Servlet1';document.mainform.submit();>

But the problem with that is the the right _call_
function is not being passed to the servlet.

so then I tried:

<input type=submit 
name="_call_do_some_function()" 
onClick="document.mainform.action='Servlet1?=_call_do_some_function()';document.mainform.submit();>