Categorized Data Validation

I want to categorize my data validation. E.g. if I select a particular item from data validated drop down, then a set of items would appear in the next column against my selected item from validated drop down.

Suppose, I am selecting an item "X" from drop down in the column A, the a set of items like 1, 2, 3, 4, 5 would appear in column B against my selected item "X" in column A.

thanks dude. This is really of great help.