Changing Proxy Settings of Web Browser

Question

I have developed a windows application ..on which there are three web browser controls...all navigate to same web URL.... But for each web browser...proxy settings should be different... currently i am setting proxy in registery...with following code

private void Change_IE_Settings(String strProxy, bool action)

{

RegistryKey RegKey = Registry.CurrentUser.OpenSubKey("Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings", true);

if (action == true)

{

RegKey.SetValue("ProxyServer", strProxy);

RegKey.SetValue("ProxyEnable", 1);

}

else

{

RegKey.SetValue("ProxyEnable", 0);

}

}
But with these all three web browser's have same proxy settings...I need all three should have different proxy settings.