Can't See Multiple Work-groups In Windows 7

As we all know, MS has changed the default workgroup names in different versions of windows. Additionally, you can rename your workgroup anything you like. I have XP, Vista, and Win7 computers, a television, BluRay player, a Wii, two printers, and a NAS with two USB drives attached. All of these -except the Win7- are wired to one of two switches. I have wireless: iPad, the Win7 notebook, Nintendo DSs. I have friend, and non-friend machines (computers, tablets, and phones) that come and go that are wired or wireless. The 3 windows computers all have the same workgroup name. All of my other units do not use workgroup names. I have a router, and two unmanaged switches, and have, on occasion, a second router. The main router, which has wired, and dual band wireless (each with two named wireless networks) nets, sees everything, by name and/or MAC address. Win7 is blind, deaf, and dumb.: it shows its own workgroup name, but no other workgroup name(s) , and, consequently, no unit on these other workgroups. It will show some wired units not in a workgroups - the television, and the printers (not the Wii or NAS). It will not show the wired XP computer! No wireless units either in workgroups or not in workgroups appear. Additionally, Win7 only shows units on its wireless network, not on the other three. The wired units it does show are not on any of the wireless networks, though it lists them on its wireless network.I have left the Homegroup, and terminated the Homegroup services. I have allowed discovery, and unlimited sharing of everything on every computer on the router, and yet the Win7 unit does not share or see well at all.Why?