Ethernet splitter question?

I have a CAT 5 running from my router to my basement. In my basement are 2 separate ethernet ports that have separate CAT 5's connected to them. I need an ethernet splitter much like a TV splitter in which one port is "IN" and the other 2 ports are "OUT". The CAT 5 connected to the router will be plugged into "IN" while the other 2 will be connected to "OUT". I do not want to connect another router, this is not an option.