For this method, I recommend you naming your maps in the following order:
Map_01, Map_02, or map1, map2 and so on. I'll use the Map_0x for this example:
//At the first time
int rand_1 = RandInt(1, 10);
ChangeMap("Map_0"+rand_1+".map", "PlayerStartArea_1", "StartSound.snt", "OtherSound.snt");
//At later times
int rand_2;
do
{
rand_2 = RandInt(1, 10);
}
while(rand_2 == rand_1);
ChangeMap("Map_0"+rand_2+".map", "PlayerStartArea_2", "StartSound.snt", "OtherSound.snt");
//At the third time
int rand_3;
do
{
rand_3 = RandInt(1,10);
}
while( !((rand_3 != rand_2) && (rand_3 != rand_1)) );
ChangeMap("Map_0"+rand_3+".map", "PlayerStartArea_3", "StartSound.snt", "OtherSound.snt");
I hope you got my example.