Cascading Validation Lists

Hi,

I've attached a sample file which outlines roughly what I'm working with.

I will have users filling out cells (e.g. on Input sheet) and want to cascade the drop-down lists based on selections made. The basis for these selections is on the LISTS sheet.

So for Area, if they choose AREA1, then the Main Activity should only have 1,2,3,4,5 as available drop-down options and if they choose 1, then Secondary Task should only have A or B as options in that drop-down and finally Supervisor option should only be XX.

My question is, is there any quick way to create these cascading drop-down lists from the structure I have currently in place on the LISTS sheet. Or am I going to have to rearrange the data on a separate sheet? I will have up to 40 'AREAS' with dependent selections.

Any help greatly appreciated!