How can I declare multiple columns as arrays where each element of
each array is a combination of adjacent (on the same row) values from
two columns?

I have three columns - the first contains a facility id, the second
contains a material id and the third contains a material id to be
referenced by the material id in the second column.

I want to compare a combination of the first and second columns'
values to a combination of the first and third columns' values to root
out 'loops' (references pointing both ways within each facility) and
instances of the second column values referring to multiple values in
the third column. There will be empties in the third column, but not
the first or second.

Thanks!
Cliff Edwards