Can you split ports and share them? Not as far as I know, they will require a unique network name/address for a piece of equipment connected.
If you need 5 ports and a link to the router, you will need an 8 port switch, dont get a standard hub. Switches work so much more efficiently.
So, the 5 housemates are being wired permanently with cat5 cable? or are they also to be wireless?