You need a powered USB hub. Most of them allow 4 devices to connect to a single USB port, but there are options to allow more devices to connect with higher ported models.
For example......USB Hub Review 2012 | Best Powered USB Hubs | 7 Port USB ...
Sorry, I cannot tell if your last post was a statement, or a question. A powered USB hub will simply allow more devices to connect. Instead of having to manually "switch" the cable from one printer to another, the hub will allow you to have both printers hooked up simultaneously.
If you are using Bonjour, it will provide service with both printers.