Hi Johncab, welcome to the forum!
If you have a pc case with room for three optical drives, you can buy three identical drives or at least three drives that are similar in their burn speed method, and then use a burning program such as Nero Burning ROM that can burn to multiple drives simultaneously.
I think it would be possible to burn to three drives at 8x simultanously on a recent pc system if you can fit the drives.
Alternatively if you can fit two drives internally and one drive externally in a FireWire/USB based enclosure, that would probably also work.
[*] [color=black]By that I mean they all use P-CAV or all use Z-CLV when burning at the same speed.[/color]