I have a field named "Month" that I'd like to populate with one of a number of available dates, depending on the tab I'm currently displaying. I could do that if I knew which tab was being displayed - is it possible to detect that?

I'd like to do it so that the field name that's being exposed will have the name "Month" and I don't need to have (eg) "Design End Month" on one tab, "Delivery Month" on another. These names would remain behind the scenes.

I'm looking for something like:
IF ([__TabName__] = "Delivery", [Month] = [Delivery Month], ... )
...or some such. Is this available?