Just create a pull-down menu for each dimension and add the items necessary using the Strings[] property (write an array with the names of the items it is to refer to to it)...You can rebuild the list of one menu (the second dimension in your case) if the other has been changed...(detect a change in the first dimension menu, then write the new array to the strings property of the second d)
The values of the pull-down menus you build an array of and wire that array to the index values property of the array.