Jon,
Are you talking about using cat5 cable and using the jacks for a computer network? If so I think each jack would require a home run to the router. If it is for phone service than it's a different story.
Looking at the leviton stuff I buy at the depot it has room on the metal fork for more wire but the snap/punch down might be tight holding two wires per spade.
Mike
It's a phone line and it's those exact jacks you're talking about, the Leviton stuff.