When I first read that RPG maker uses the Caterpillar party system, I was hoping the same thing, sigh how about if I don't want a bunch of char following me. It's definitely not a major issue, but still, it seems weird to force people to use that format(why didn't the developers make it a option, instead of sticking us with it, It's a weird mechanic to have as a default setup), but I would think someone created a script to do away with that already, if at all possible.
Edit: Lol KSJP beat me to it. Yep that would do it, I forgot you had access to all the scripts that RPG maker uses for its defaults, that makes things easier(no need for a override script, just edit the script already there).