seperate commits for objects already updated in index?

Hi,

Dumb question, imagine you made changes to a few files, and ran 
update-index at various stages in between:

$ git status
#
# Updated but not checked in:
#   (will commit)
#
#       modified: foo/ChangeLog
#       modified: foo/whatever
#       modified: bar/ChangeLog
#       modified: bar/other

The changes in bar/ are unrelated to the changes in foo/ - how do you 
commit each seperately? Git doesn't seem to want to let me:

   $ git commit -o bar
   Different in index and the last commit:
   M       bar/ChangeLog
   M       bar/other
   You might have meant to say 'git commit -i paths...', perhaps?

git commit on its own wants to commit all the above files.

what's the silly thing I've missed?

Thanks.

regards,
-- 
Paul Jakma	paul@clubi.ie	paul@jakma.org	Key ID: 64A2FF6A
Fortune:
Never tell a lie unless it is absolutely convenient.