If you're looking for something along the lines of Command and Conquer, then forget it. It would lag a computer to hell and back. The only reason it doesn't do that in an actual C&C game is because those games use a compiled language which processes MUCH quicker than RGSS(used by RMXP) because the computer has to "translate" RGSS to computer code every damn time something is being processed before it can be understood by a computer.
I know I just came off as a bitch but I hate seeing script requests like this because if you'd use a little common sense, you'd realize that if something like that could be done with an amateur game maker like RMXP then there'd be a lot more games of this sort out there, professional AND amateur alike. Don't take the above or below personally(kind of hard not to I guess) but I truly hate it when I see script requests of this nature because they'd be nearly impossible due to the fact that it'd require a complete overhaul of the system thus making it more efficient to code your own engine and system in a compiled code to optimize the performance of your game.
This is why I've considered moving on from RGSS to C++. Wow. I can be a total bitch when I'm tired. Again, I apologize for the above but PLEASE use a little common sense or atleast learn a little about RGSS before posting a script request like this because then you'll realize that it's not really practical to use RMXP for something like this.