First let me credit Joseph Rubin's website as the source for this formula:

=INDEX($A$2:$A$13,(ROW()-2)*3+3)

to be used to grab every third value from a list (range) in $A$2:$A&13. The
results look like this:

a c
b f
c i
d ...
e
f
g
h
i

My problem is that I need to calculate from the bottom up of a range so that
the last value is always at the end in the manufactured "every 3rd value"
list. So, for the other end of the alphabet, for example,

r
s
t
u
v
w ...
x t
y w
z z

I know I can just use =z to get started with the new column end, but I am
struggling with the formula reversing up from there.

My thanks in advance for any help! Cheers! Brad