Swap movie clips?

Hi! I making an rpg that involves being able to change characters on command.
Is there such thing as a ‘swapping movie clips’ code? I heard of swap depths, but nothing else. What I would like is that if the player hits a certain mc it switches to the new specific MC; such as if the player hits a weapon, it switches mcs to the player holding it AND, if they press a button, the main hero mc completely switches to thier choice of player, right there on the map with the same controls. What I have been doing is making the main mc completely switch frames with the new mc when the player chooses, but as you could imagine, this takes up a lot space. I have a ton of controllable characters, meaning that for each switch, I would have to make a whole new frame for it of every frame the player might be on at that moment! Not wanting to have 2 million of the same frames everywhere, I tried just putting all the controllable mcs on different layers on the same frame and dropping their alphas to zero so that I could just action script everything to change alphas for the hero mcs on command, or when they touched an item… This made EVERYTHING slower than a dead rock, and all the background ‘ground’ mcs such as trees and rocks, wouldn’t respond anymore. I have no idea on to build this code, but here is something to start off with. Thanks.

[FONT=Times New Roman][SIZE=3]onClipEvent(enterFrame){[/SIZE][/FONT]
[FONT=Times New Roman][SIZE=3]if(this.hitTest(_root.girl)){[/SIZE][/FONT]
[FONT=Times New Roman][SIZE=3]_root.tree.swapDepths(1);[/SIZE][/FONT]
[FONT=Times New Roman][SIZE=3]}[/SIZE][/FONT]
[FONT=Times New Roman][SIZE=3]}[/SIZE][/FONT]