Combining 5.1 and 2.1 systems on the same output

For my new apartment, I'm buying a new set of the Logitech X-540 5.1 surround sound computer speaker system. I also currently have a Logitech 2.1 system that I've been using. What I'd like to do is use both of these systems from the same output (either my computer or ipod), so I'd be using all 7 speakers and the 2 subs.

In order to do this, should I simply get a splitter to split the single output (computer or ipod) and have it fed to each of the two speaker systems or is there a better way to do this? I've been told the sound quality might not be as good on either if I do it this way. Has anyone done this before or have a better way to go about doing it?

Also, would I need any special sound card on my computer to support doing this and would the iPod support it?

Thanks.