Hi MarthaSue,

As you say its pretty difficult to get a handle on exactly what you
need or want to do but if it can be done with Data Validation then
Deborahs site is the best reference l can suggest.

It seems to me that you probably need to look at:

1) Dependent Dropdowns from a sorted list
2) Under data validation 'Tips & Quirks' look at Data validation
dropdowns & Change events.

Effectively picking a selection in the 1st list will require picking a
selection from a 2nd list, making that selection will trigger an event
(macro) depending on the choice. This macro could be the insertion of
rows.

I do not know what level of Excel / VBA you have but l guess you could
describe the above as being intermediate / advanced.

Hope this helps

Regards

Michael.