That's right. It would work if your citations were empty, but in this case, it would break them. What you would really need here, I think, is a way to add the date to the source itself, assuming that all census entries were made on the same day, and without that, I guess that most put the census date/year in the source title, which may not be very consistent with the rest of your work.A large number of people in my database appear in a particular census, which is one source. So, using the census as the source, there will be a separate citation for each individual (for birth, residence, occupation, etc. information), and each citation will have its own Volume / Page entry to match the individual place where the respective person lived.If I have understood your suggestion correctly, collapsing all to one is not an option.