Basically, you want to add people from #1 that aren't in #2, right?
Copy the worksheet from the 1st file into the 2nd file and name the sheets
NewData and OldData.
I assume that on each sheet, the names are in column A, addresses in column B,
and you have a header in row 1
On the OldData sheet, cell C2, put this formula:
=COUNTIF(NewData!$A$A,A2)
and copy it down through the last used row.
Use Autofilter on OldData sheet to display only the rows with an 0 in column
C.
Edit/Copy the visible rows, and paste them at the bottom of the list on
NewData.
Then delete column C on the NewData Sheet.
If this isn't what you want, we need more information