I'm trying to "calculate" a field in a Query and/or Report based on a series of inputs in a Table. There are basically 12 possible outcomes based on data in several different fields. A simplified example follows:

Inputs are: A, B, C, and D
Possible outcomes are: W, X, Y and Z

If A<=50 AND B<=25 AND C<=6, THEN W
If B>=51 AND C<=10 AND D=0, THEN X
If B<=35 AND C<=40 AND D<=10, THEN Y
If B<=35 AND C>=41 AND D<=10, THEN Z
and so on...

Other than a very complicated series of nested IIF and AND functions, what would be the best way to go about this? Would a Table Lookup be easier?