Then just plug the router into the e3000 regular LAN port and use it as a dumb switch. Nothing fancy need be done. I am doing the exact same thing with mine. I just plug a Ethernet cable from a port on my router to one of the switch ports on the e3000.
All PCs connected to the e3000 wirelessly become just other PCs on the lan as if they were plugged in to a switch. The e3000 is essentially a "wireless" switch if you will.
