Your best option would be to stores the values of each combobox into cookies
(or insert them dynamically into the source code of the page if you are
using ASP instead of HTML pages) and use parameterized queries as the source
of your combobox in the same way that you will do for one combobox.
Using the *standard way* of having one combobox as the GroupFilterControl
for the GroupLevel is not a good idea if you want more than one combobox;
Sylvain Lafontaine, ing.
MVP - Technologies Virtual-PC