multiple Relation

I want to use multiple master detail relation on one form .

my situation is :
I have tree tables as countries -states - cities

I want to build relation between
countries and states , states and cities on the form

First I tried using data environment . I build command objects as

countries
- states (relation : countries.countryid=states.countryid)
-- cities (relation : states.countryid=cities.countryid and states.statesid=cities.statesid )

When first opening the form relation work correctly. But
then datagrid ,I use for representing cities, doesn't refresh corretly. (Even if I change states or countries nothing change in the grid.)

Then I tried using dataform wizard but I can relate
only 2 table. it is not available to relate more than two table.


I dosn't want to write hard code .
How can I solve this problem .

Is there any other way to solve this problem.

Thank you for your help.....