use one lookup to reduce the records in another lookup

use one lookup to reduce the records in another lookup

I have created a function and form to copy a few fields from one record and paste in another record.  I select the record to be copied using a button on the report which also calls a form where the record to past to can be selected. The problem is the list of records to select from when choosing where to paste is 4000 records long.  This makes it difficult to find the record to paste to.  I want to reduce the selection by using another field that is linked to the selection or in other words I want two criteria to select the records to choose from.