Not a spammer

Please review.

I need assistance and would like to post the following request to the forum:

I'm trying to formulate a solution in Drupal 7. But need advise on the smartest functional way.

Example:

I have 20 BUSINESS UNITS in a selection list field or taxonomy. Each BUSINESS UNITS has 8 BUSINESS ACTIVITIES.
But each BUSINESS ACTIVITY has like 30 BUSINESS FUNCTIONS
and each BUSINESS FUNCTION has like 99 BUSINESS CATEGORIES.

When you finally select the BUSINESS CATEGORY, a read only field needs to pop up with a unique code like XX-XX-XX-XXXX (Codes are provided)

So,
If i select one of the BUSINESS UNITS like value1 then their 8 BUSINESS ACTIVITIES APPEAR.
Then If I select one of the BUSINESS ACTIVITY like value23, then their 30 BUSINESS FUNCTIONS APPEAR.
Then if I select one of the BUSINESS FUNCTION like value84 then the unique code appears.

Being fairly new to Drupal (and in love with it), I've tried the example using Content Type Nodes as well as Taxonomy and Even Webforms. Using Conditions and/or Webform Conditional modules. They certainly would work, but required hundreds of hours of creating field after field with condition after condition and each selection list must only appear on condition that a specific value is selected.

Far to complex:8 units x 8 activities x 30functions x99categories, then each final category needs to render a result and each is conditional on the previous selection. = (A very large number)

There has to be a more sensible way of doing this (perhaps a table type module)

Very similar logic to Country > State > Area > then displaying the correct Zip

If this were just fields the database or an excel spreadsheet, then its logical and easy with tables and conditions and filters.. But we talking Drupal7 :-) .

When the final UNIQUE CODE is displayed, its gotta write the results to the database and email off to a specific user (Will try rules for that)

I have even tried the hierarchical module, but the csv import module does not allow duplicate values.

Thanks for your patience and for reviewing. Desperately looking forward to your genius!?