[Zope] ZPT/ZSQL Two drop down menus

Hi, In a ZPT, I have a form with two drop down menus (address and street) and submit button. The values of the second drop down (adresse) depend on what the user selected in the first (street). The values of both list come from ZSQL method. Is it possible to catch the value of the selection of the first drop down list (with the onChange event?) and pass it as argument to the ZSQL method of the second list. Thanks a lot Etienne