Now that I think about it, using PHP would require me to modify the shopping cart software. The modifications would end up being be removed after updates. I figure if I use .htaccess I wouldn't have to keep adding the code back after updates. I still haven't ruled it out as an option, though, if it works best.
Originally Posted by Andy101
You guys are the best for helping! I'll try the .htaccess suggestions and see what happens.