Capistrano Deployment to Multiple App Servers w/Mongrel

Hey folks,

I have an app deployed across multiple app servers with Capistrano as
follows:

role :web, “app1.domain.com”, :primary => true
role :app, “app1.domain.com”, “app2.domain.com
role :db, “db1.domain.com”, :primary => true

set :mongrel_conf, “#{current_path}/config/mongrel_cluster.yml”

This works OK, but I would really like to change the mongrel
configuration so that it runs on a different address on app1 & app2.

Specifically, I want app1 to listen on 127.0.0.1 and I want app2 to
listen on 172.16.1.1.

Being able to change the number of mongrels & start port would also be
handy.

Anyway, I have found plenty of reference to people deploying to
staging & production environments and changing stuff out that way, but
this is just to change the config per-server in production.

What is the most elegant way to do this?

Thanks,
Dave