for the video, you need 3 rca splitters (one for the green, blue, and red each - or one if you use the yellow video cable) and the nessary cable to go to the other room.
for optical audio, i know of no splitter, but i beleive you can use the stereo rca cables at the same time as the optical audio.
i am not certian of this. you might want to check that out first. (i dont use optical)
i dont know what your setup is like, but if you have a componet system, it could output the audio in stereo as well as to your speakers, but this would depend on your setup.
having an all stereo setup would be very easy - just use 2 splitters the audio.
so, each splitter would look like this: (each "----------" is a rca cable of however long you need it)
also, splitters have 2 female connection and 1 male, so depending on how you do the cables and stuff, you might (probably) need some female/female adapters