Conditional Population Of A DropDownList Control

I have two DropDownList controls, ddlGroup and ddlLocation.

The contents of ddlLocation will be determined by the selection of ddlGroup. A better explanation is as follows:

ddlGroup =



ADVANCED DEVELOPMENT

DESIGN

HEAD TEST

INK R&D

JETTING

PROCESS

RELIABILITY



The SQL query that shows my logic is:

IF @Group = 'ADVANCED DEVELOPMENT'
   SELECT Location FROM tblLocations WHERE Location like 'AD%'
ELSE IF @Group = 'DESIGN'
   SELECT Location FROM tblLocations WHERE Location like 'DE%'
ELSE IF @Group = 'HEAD TEST'
   SELECT Location FROM tblLocations WHERE Location like 'HT%'
ELSE IF @Group = 'INK R&D'
   SELECT Location FROM tblLocations WHERE Location like 'INK%'
ELSE IF @Group = 'JETTING'
   SELECT Location FROM tblLocations WHERE Location like 'JT%'
ELSE IF @Group = 'PROCESS'
   SELECT Location FROM tblLocations WHERE Location like 'PR%'
ELSE IF @Group = 'RELIABILITY'
   SELECT Location FROM tblLocations WHERE Location like 'RL%'


I need to define the content of ddlLocation after a selection is made in ddlGroup; how can I accomplish this using Visual Web Developer 2008 Express Edition?