How to split 5.1 sound between PS3 and computer?

[CK804]

I currently have a Logitech G51 speaker system, a PS3 and an Intel DP45SG motherboard. The PS3 is connected to a Dell 2709W via HDMI. How would I go about splitting the analog 5.1 inputs on the G51 between the DP45SG and the PS3 without damaging anything? Both sources may occassionally output sound simultaneously. Would using regular 3.5mm stereo cable splitters such as this one work?

 

[polarbear6]

well i did had a situation like that i have used some parts which i cannot tell cause i asked for them in my local language

i use it for my pc and my ps2
but they dont output power together

what i can say is
i used a converter to get my signal from 3.5 mm to another jack(i dont know what they call that they somehow look like a hd pins u know a two polar wire i guess arhh hard to define)
then to a switch which lets me choose the output and then back to conversion to 3.5mm
but it is not at all clear so i sold my ps2 on ebay
and NOW IAM HAPPY

 

[krnmastersgt]

I don't see any reason why it wouldn't work, having 2 outputting sound at once might get annoying though but I've done something similar, albeit not with a 5.1 surround sound system but the principle is the same.