How to reference 100's of items with corresponding triggers to designate an end date.

Hi -

Our agency has a formal record retention policy that lists over 100 types of records that we store or have digitized in-house.  

Question to answer/example:  If the documents for Site A fall under Record category 1, they  should be destroyed on 1/1/11, which is 100 days following the trigger date.

I was able to create the formula that completes the equation and creates the date of destruction on my retention policy sheet, but I need to refer to that formula when a document is added in one of the many sheets that list all of our individual documents.  

How do I reference a corresponding set of cells listed in my main sheet automatically, when I assign the record type to a document  in a separate sheet?

In this case I have a form that the staff member fills out and identifies the record type.  The new document is populated onto an inventory sheet.  At that moment, the document should be automatically assigned a disposal date based on the retention policy.  

Thanks for your help.

Sarah