Never done exactly this on a recording, but I have used it to good effect with midsized choirs I have directed -- have one of every four singers on each voice part use normal diction with all consonants, and the other three fourths sing without the hard consonants. The consonants are present, and sound as if pronounced normally, but you don't get all the hisses and stutters you get with everyone trying to nail an 's' at the same instant.
It does take a bit of practice, but rather less practice than getting all the timing of all the consonants exactly right!
The important thing though is that some of the group are pronouncing them normally, so the listener hears nothing that sounds unusual.
-Glenn