Hi Excel geniuses

I cant figure this one out. Can you help pls?

Imagine a time line left to right in monthly increments on a worksheet (A
say) and rows underneath.

I would like to set up a formula within the cells in worksheet A, that
dependent on whether that cell's date value lies within two date ranges held
on worksheet B (2 cells start/end date: StartDate1, EndDate1 : StartDate2,
End Date2), it returns either one of two cell references (2 cells holding
values) or a zero.

The idea being that changing the date ranges in worksheet B will update the
cells on Worksheet A..

Please help I said I thought it could be done and now Im not so sure..

Thanks guys! Youre fantantastic