Show / Hide index menu

I need a page menu for Wordpress/ or drop down form.

I need on main drop down to be on the page. When the customer selects the drop down the first category listings appear:

ASIA & AUSTRALASIA
AFRICA & MIDDLE EAST
AMERICAS
ASIA & AFRICA COMBO’S

Depending on what they select a new drop down will appear and give options for that selection.

When the next option is selected then from that drop down they will be taken to the relevant page within the website.

The show/hide will only show a drop down from what has been selected before to get to the page information that is required.