How can one run mutiple idrac 5 cards on the same network?

So I have 4 2950iiis and 1 1950ii i would like to put drac cards in them all to access on the go.I have one set up and it works fine but now the ports are now used on the router so I dont know how I would be able to hook up 4 more cards off one network /external ip address / domain.

Any ideas?

Thanks for any advice.