How to obtain a cascading text in ASP.NET Autocomplete textbox

Hi All,

I have the following two tables.

table:products
pid pname
1 samsung
2 apple
3 sony
4 nokia
5  acer

table:apple_products
aid aname pid
1 iPhone   2
2 iPad    2
3 iPod    2
4 iTune  2

I have a ajax autocomplete extender mapped to a textbox. If I type a in the textbox the webservice pulls the candidate keys(apple,acer) from the table "products". Now what I want is if I type a in the text box it is returning apple and acer, and if I select apple and hit a space then it should pick the values from the table "apple_products" since it has a foreign key reference to the products table and also that second value should not overwrite the first value, I mean the textbox should contain a cascaded value "apple iphone" (if I select iphone in the second popup).

How to achieve this ?

Thanks,
Sachi