MightyGem,
It sounds from what you have said that you have a mobo with integrated sound and external speaker / mic sockets, but no means of coupling the internal CD-ROM output to the sound card.
If that truly is the case (very strange in this day and age), I don't see a problem with plugging external speakers into the headphone socket in the CD - I've certainly done this for test purposes.
I've not seen anything like a "splitter" socket to allow both headphones and speakers to be connected at the same time to the external CD output, although I can't see why anything catastrophic should happen. Just seems very messy with lots of wires trailing around the front of the PC under the CD tray
Have you considered buying a PCI sound card? It seems like a cleaner solution to me.
SD