I am trying to set a value in several cells when a single condition is true.
For example, if A1 = B1, then I want to set all cells C3, D3, E3 and so on to
a given value. For instance, when IF(OR(A1<0, B1<0) ... ), I want to set a
bunch of cells to zero. (I realize I can put an IF in each of the target
cells, but this seems there should be an easier way.)

Many thanks for your help.