Am working on a book where most chapters are simply labeled Chapter One, Chapter Two etc., and this has been achieved easily enough with \setuplabeltext[chapter=Chapter ]  (also including  \setupheads[conversion=Words] to get One, Two instead of 1 2).

But several chapter labels need to have a date range after them, e.g. Chapter Three: 1820-1880.

I have tried introducing a new \setuplabeltext[chapter=Chapter: 1820-1880 ] just before the \startchapter command, but this results in:

Chapter: 1820-1880 Three (and I also hope that introducing this does not also affect Chapter Four since that will have a different set of dates).

How can I get a specific labeltext set up so that the result is Chapter Three: 1820-1880, and also ensure that other chapters either return to just the chapter number or, if needs be, can also indicate different date ranges? I have looked everywhere on the wiki for ideas to help me, but so far no luck.

Julian