Swapping meshes

I have a menu set up that lets the player choose a location, and I want it to display a mesh of the country based on the current selection. What I want to ask is what would be the most efficient way to replace the mesh for each choice?

I hope this is clear.. :roll:

For example:

Choice one shows a mesh of Japan, replaces Germany or USA mesh.
Choice two shows a mesh of the United States, replaces Japan or Germany mesh.
Choice three shows a mesh of Germany, replaces USA or Japan mesh.

My idea was to start with an empty and swap that with a country mesh. Maybe I'm missing it but I'm not seeing anything in the documentation about how to replace an object with another.

Here's my (currently bare bones) menu code:

Code (csharp):

1. var arenaselection = 0;
2. var AS;
3. var arenaselectiontext = "Select";
4.  
5. arenaselection = PlayerPrefs.GetFloat("ArenaSelection", AS);
6. return arenaselection;
7.  
8. function OnGUI () {
9.    
10.     GUI.Label (Rect (30,460,125,20), "Choose an Arena");
11.     GUI.Label (Rect (30,480,150,20), arenaselectiontext, "box");   
12.    
13.     if (GUI.Button (Rect (30,480,25,20), "<")) {
14.    
15.     arenaselection = (arenaselection - 1);
16.    
17.         if (arenaselection == 0) {
18.             arenaselection = 1;
19.         }
20.     }
21.  
22.     if (GUI.Button (Rect (155,480,25,20), ">")) {
23.    
24.     arenaselection = (arenaselection + 1);
25.    
26.         if (arenaselection == 2) {
27.             arenaselection = 1;
28.         }
29.     }
30.  
31.     if (arenaselection == 1) {
32.        
33.         arenaselectiontext = "Japanese Budokan Hall";
34.    
35.     }
36.  
37. }
38.        
39. function Update () {
40.     PlayerPrefs.SetFloat("ArenaSelection", arenaselection);
41.    
42. }

Thanks for any help!