Is there a way to have 2 columns with dropdown List Validation where if you
choose an item in List A it will automatically populate List B with the
available choices?
For example, Column A contains a list of Car Makers referred to by a named
range somewhere else in the sheet or workbook. Honda is chosen in Column A
so Column B should have the list of Honda vehicles to choose from.

I had assumed arranging the range data so that in one column all the car
makers are listed and to the right of each car maker the models would be
listed in the cell to the right, however many it took for each.

I want to limit the dropdown to show only the valid choices.