Hi,
To the best of my knowledge there isn't a simple multi-dimensional lookup,
however, if you only have 2 options then it's relatively straightforward.
=if([lookup #1],[lookup #2],[lookup #3])
where:
lookup #1 : is the intial lookup to decise which sheet you want to use to
get your final values
lookup #2 : is the lookup to get final values from result sheet 1
lookup #3 : is the lookup to get final values from result sheet 2.
If you have many options then it gets a bit more complicated but can be done.
Post up if this is the answer you need or if you need to choose from many
options.
HTH
Giz