Drop Down Cell Help, After choosing a selection in cell A, Cell B opens a group.

Cell A contains many categories. After electing the category, I want to be able to choose from a list that is only for the selection. If KS (in red) is selected, call up the items in red to select from the group in red. I am building a category code for parts that are configured differently. Part configuration differs by allowable content. Iten in cell A in blue is item two with different configurations.

Perhaps http://www.contextures.com/xlDataVal02.html