Arrangement problems.
 

I need some help with arranging rows of data.... here is a
simplification of my problem

I have two seperate lists

Z Y X M
A 1 2 B 4 6
B 7 9 A 5 8
C 7 9 D 7 9
D 8 8 C 6 8

I need to merge it so it is like this

Z Y X M
A 1 2 5 8
B 7 9 4 6
C 7 9 6 8
D 8 8 7 9

so that the values of A in the first row merge with the values of A on
the second row of values into one neat row...The second list has twic
as many entries as the first but should have all the same corresponding
entries that the first list does...