How do I configure the Airport utility to allow more than one rule per port?

How do I configure the Airport Utility (AU) to allow more than one rule per port?

I am on a home network, with broadband cable modem. I have my airport extreme connected to the broadband modem. I have 2 servers in my home that need to be accessed remotely from time (SSH), and they also serve data for an iphone app, so I'm using a variety of protocols. The problem I'm running into is that AU seems to only allow one rule per protocol, so if I go to add another address for access on a specific port that is being used by one of my servers, AU tells me "The Port Mapping Entry Already Exists".

I need to be able to allow SSH on both of my servers, for instance. Am I missing something? Is this doable with AU?

Thanks for any insight.

Khalid