I have a formula in a worksheet:
=IF(ISNA(VLOOKUP($B15,Question1!
$C$2:$H$20,,FALSE)),"","X")
in which it is doing a look up at a worksheet
called "question1"

in another cell adjacent I would like it to perform the
same but look at worksheet "question2"

Simply:How can I fill a formula across and have it look
at the next worksheet in a sequence?

A little more difficult yet more generic in use:
programming the function to allow the user to insert the
name of the function as a sub function either
sequentially or in some list it can pull from.