I am in the process of comparing two Excel reports on users where the
data is (or should be) identical, but in one some of the user
information has been grouped into a single identifier. Unfortunately,
I basically need to take the other report, which has anywhere from 8 to
25 rows for a given user and compare it to this one with a consolidated
listing.

For instance, it would be something like this:

Consolidated Report:
User1 identifier1
User2 identifier2
User3 identifier1

Base Report:
User1 infoA
User1 infoB
User1 infoC
User1 infoD
User2 infoC
User2 infoD
User3 infoA
User3 infoB
User3 infoC
User3 infoD

What I basically need to do is consolidate the rows for any user that
has the same grouping of information in a single column. So User1 and
User2 would be reduced to a single row (or flagged with a certain
color, tagged in another cell, etc... anything to automate this a bit)
and I would then replace the "info" column with identifer1. I have
been playing with this off and on for about a day, but I haven't been
able to find an efficient means of consolidating this data so that it
is in a form where I can easily compare the two reports.

I would really like to avoid doing the 4500 or so rows that are in the
base report by hand, given that there are nearly 400 users. If there
are any solutions to this problem that would enable what I'm looking
for, I would really appreciate it.