I can get as far as getting excel to recognize matches by concatenating the information from two columns(let's say in a new column C), then reversing the text string of the concatenation (let's say in a new column D), and telling column E to =IF(MATCH(C8,$D$8:$D$1996,0),1,0).

But all this does is return a 1 in column E for matches 1-3, 3-1; 2-6, 6-2; 12-13, 13-12, etc. What I really want to be able to do is get it to return a unique result for each unique pair, recognizing that 1-3 is not different from 3-1 but IS different from 1-4 and 4-1, which, in turn, are not different from each other.

Any ideas?