DD-WRT - LINKSYS CISCO E1000 ROUTER REPEATER BRIDGE WiFi Wireless-N N 300Mbps Ready HOTSPOT [DD-WRT PREINSTALLED]

I want to set up a small Network for this room of the house the goal of this network is to connect four devices together mainly for file-sharing purposes but they also need to have internet connection so I already have a network in my house basically there is a wireless router that provides wired and wireless network and internet connection for my network devices so one solution probably would be to connect the devices in room B to the same wireless router the same way the rest of the devices are actually connected this way they're connected to each other as well as to the internet right yeah but it would have worked for me that way for two reasons number one I want to be able to somehow separate the network in this room from my home network basically I don't want anybody from outside be able to access the devices in this room so the access should be within this room only number two I d