I program a bit myself, but I like to think I know when doing something by hand is easier than coding it up.
Since the major problem was going to be making sure two authors weren't in the same group, I first split the stories into 12 buckets alphabetically by first name. So all the "Johns" were in the same bucket. Then I just drew lots 1-10 for each story in the bucket, and that's the group they went into.
I'll admit to fudging a bit and picking the shortest story to be the 13th story in the extra sized group, and deciding beforehand that that group should be #6.