I am using a combo box to identify a selection sequence but I can't figure out how to point to the next available combo box -criteria based on the first item:

Box one possibilities - Heartland or Vitco
If Heartland is picked then 4", 4-1/2", triple 3", Dbl 4"
If 4" Chosen then available options of Grey, White, Fern,
Beige.
If Vitco is picked then triple 4", Cedar as options
If Cedar is picked The Red, Beige, White, Blue

How do I do this in excel for an order form?