ICS - Router newbie question

Does a Cable/DSL router have to be connected directly to the incoming cable line in order to split a connection?

Here's the deal. The cable company allows up to 3 simultaneous connections on my line. I am building another computer and want to be able to get all 4 on the internet, which I plan to do with a 4 port EtherFast Cable/DSL Router. However, I do NOT wish to unplug 2 of the original computers from their current position unless I absolutely have to.

So, can I plug the router into one of the regular ethernet ports on the hub that is connected to the cable modem, and essentially draw one IP address, and split that up seperately from the other 2 computers?

Man that sounds confusing even to me.... let me explain this way...

4 Comps
1 Modem
1 Hub
1 Router

Modem --> Hub --> Comp1, Comp2, Router --> Comp3, Comp4

Will this work?

Also of note because I'm not completely familiar with how the Cable companies have their stuff running.... but I do know that only computers whose NIC card Mac Addresses I have called and "registered" with AT&T will work in my current configuration (being straight connect to hub to modem)
Does the router bypass the Mac Address checking? If not, how can you get this to work?

you shouldnt have to worry about it, some companys configure the connection to work with a specific mac address. if that is the case you have to change the mac address of the wan port of the router to match the one in their records.

how do you shoot the devil in the back? what happens if you miss? -verbal

yes, that setup will work.

<i>It's always the one thing you never suspected.</i>