You may do.
Merge multiple excel in one then convert it to txt.
Have a look here!
http://forum.chandoo.org/threads/merge-sheet1-from-multiple-workbook-using-single-connection.33746/
AGGREGATE is a very fantastic fn but in case you have xl 2007 then you may try this one.
=INDEX($E$1:$E$10,INDEX(LARGE(($C$1:$C$10=G3)*ROW($C$1:$C$10),2),,))
Something like this...
Dim s As Byte, str As String
s = InStr(1, stremail, "@") + 1
str = Mid(stremail, s)
s = InStr(1, str, ".") - 1
extractDoamin2 = Left(str, s)