P2P to several computers: Port forwarding?

Soemthing I have been meaning to ask for a while now. I am an occasional user of P2P (client utorrent) but sometimes it is on my desktop and sometimes on my laptop. But I always have to change the Port Forwarding rule in my router (Netgear DG834GT) if switching from one to t'other. Is this normal or is there a way of setting things up so I can have utorrent running on either computer without messing around with the settings like this?

Just setup a portforwarding rule on the router for each machine but use different ports eg 9991 for the pc and 9992 for the laptop and configure the application on the appropriate pc to use the applicable port.