Excel spreadsheet cascading drop down lists

I need modifications to an excel spreadsheet to allow users to select values from a data table based on a cascading set of drop down tables for example select level 1 and only be presented with certain options in drop down level 2 and based on level 2 only allow selection of certain values for level 3

The actual lookups are long with lots of values so the drop downs must be able to result in a unique value

Time is critical so must be able to start immediately and deliver within 24 to 48 hours