How to dinamically populate and filter ToolStripDropDownButtons

Question

C# WinForms
In a project I have an accdb database (db01) - a table (tb01) - and three columns:
* col_Country
* col_City
* col_Companies

On Form:
* ToolStripDropDownButtons - btnCountry and btnCity
* dgvCompanies

btnCountry shuld have items as unique (distinct) values from col_Country - alpha sorted - first value selected

So, when I choose a Country:
* btnCity should have items as cities in the chosen Country - alpha sorted - first value selected
* dgvCompanies should have companies in selected City.

Is it too much asking ?