375402 Simple Excel VBA Combine Scrip

I have a very simple VBA code I need I just don't know how to do it so posting here; I have several sheets in a workbook with multi-column records. Many of these records are partially identical and need to be merged. Generally this is because one record has values in some fields and the other has values in others. The process is essentially; I identify one or more fields that indicate what constitutes a match (e.g. Field1 and Field2 must be a match to be considered identical) Then create a new record (row) which uses the fields from each record that has values in it so I have a new complete record. This is all obviously very easy code (User Choose Key Fields, Code combines into one record based on which fields in which record are non-null, which obviously will not be either of the ones I indicated as key). The only snag in this which will be a very few cases is sometimes there will be values in non-key fields in both (or all three) records that have values in them. In this case I need to indicate which to keep. So I am hoping as it steps through doing the process a dialog box can pop-up and allow me to choose which values from the field(s) that have conflicting values. As I see it would have a dialog box with Field1: Value [x] Keep Field2: Value [x] Keep So I can keep either or both. Both would store both with a colon separator.