I want to create a formula that allows me to select a list in one cell having
selected an item from another list.

An example of what I mean. If I have an expense account and have Expense
types and Expense Sub-Types.

I want to select an Expense Type in one cell from a given list and then in
the next cell I am presented with a list associated with that specific
Expense Type (Sub-Expense Types). I.e.Expense Types in list 1 might be:
a.Entertaining
b.Travel and
c.Communication, etc.

Sub Expense Types might be for
a. Customer Entertaining & Staff Entertainingfor
b. Train, Car, Boat, bus and for
c. Land Line, Broadband, Fax Line, Mobile, etc.

So by selecting Communication in cell 1 (from list 1: Expense Type), I am
presented in cell 2 with the associated Sub-Expense list; Land Line,
Broadband, Fax Line, Mobile.