When I say: "What I don't understand is what identifies that first record on the second sheet", I know that the connection is to apples to apples and eggs to eggs. What I don't know is what is the secondary key...i.e. what makes the first record...well.. the first record.

If you don't understand my questions, and it is clear that you don't up to now, then I probably can't help. Sorry.

Forget these games. This is getting nowhere. Attach a sample of your actual sheets.