QUOTE(Philharmonia @ Oct 12 2005, 06:10 PM)
Thanks. I thought it might be a double choir, separate groups of SATB as some choral works have this arrangement.

yes - I guess it could well be, just that I've never heard it called that.
Our conductor might sometimes refer to one of the voice parts "splitting", although it's more likely to be eg "altos divide here". But I've not come across it used to describe the sort of choir you have.

Antiphonal - when half the choir has the wrong music!