Completing from different ssh config file

[Jean-Rene David <jrdavid@xxxxxxxx>]

I use the following function to log in to certain hosts:

foo() {
   ssh -i ~/.ssh/id_rsa.foo \
       -F ~/.ssh/config.foo \
       "$*"
}

How would I configure the completion system so
that the hostname is completed from
~/.ssh/config.foo when I use this function?

Right now the hostname isn't completed at all
because the context isn't recognized as a call to
ssh.

Thanks,

-- 
JR