When I open an Excel - by default I see 3 workseets. My question:
I have 3 separate excel files. How to create from 3 excel files one
file with 3 worksheets?

I have 3 excel woksheets - A1, A2, A3. Each of them have a column
called SSN. I want to add to a new column to A1 with the following
walues:
if SSN from A1 exist in A2 - the value will be "A2"
if SSN from A1 exist in A3 - the value will be "A3"
if SSN from A1 does not exist in A2 and A3 - the value will be "N"

Can you give me a hint how to do it?

Thanks,

Zalek