Dynamic generation of list of values in a column based on values selected in another colum

Hi,

I am trying to populate a list of values suppose in columns B1, B2......Bn in sheet Values based on what I select in column A1, A2.......An. The values are given for different sets in the Data sheet. Suppose for name A possible values are x, y, z, similarly for name B possible values are s, t, u, v. In sheet Values I want the A columns as list of selection as well as B columns also as list of selection based on what I select in corresponding A columns. I would prefer simple use of IF-Else, Data Validation etc. rather than writing macro etc. Attached is the file for reference.