biblatex and biblatex-chicago: how to cite using only the first location in a list of locations?

I'm using biblatex-chicago to generate my footnotes. I have lots of bib entries that have a list of locations in the location field, like location = {LocA and LocB}. But I want my generated citations to only show the first of these, so that the citation would read Author, \emph{Title} (Publisher: LocA, NNNN) instead of ... (Publisher: LocA and LocB, NNNN).

Is there a way to get biblatex to do this automatically, instead of having to edit my bib database and throw away information? I tried the biblatex option maxitems=1, but this produces "LocA et al." in the location spot. Could what I'm after be achieved either through package options or--though this would be much less desirable--by modifying some aspect of the bibliography style?

More detail:
A typical .bib file entry looks like this:

Author = {McGann, Jerome J.},
Location = {Chicago and London},
Publisher = {University of Chicago Press},
Subtitle = {A Critical Investigation},
Title = {The Romantic Ideology},
Year = {1983}}

But now I'm producing text for a house style where I should only cite the first location, so I want \footcite{mcgann:romantic} to produce a footnote reading (roughly)

1. Jerome J. McGann, \emph{The Romantic Ideology: A Critical Investigation} (Chicago: University of Chicago Press, 1983).

and not the output I am currently getting from biblatex-chicago, which is

1. Jerome J. McGann, \emph{The Romantic Ideology: A Critical Investigation} (Chicago and London: University of Chicago Press, 1983).

Many thanks for any help you can give!
Andrew Goldstone