I'm trying to concord data between two excel files, but unfortunately some
information was dropped from one file to the next. I was wondering if there
is a way to sort ranges such that the contents of one column match up to the
contents of another column. So, for example this:

a/1 = a/1
a/2 = a/3
a/3 = b/1
b/2 = b/2
b/3 = c/2
c/1
c/2

would become this:

a/1 = a/1
a/2 = -/-
a/3 = a/3
-/- = b/1
b/2 = b/2
b/3 = -/-
c/1 = -/-
c/2 = c/2