How i do this stuff is:

I just add random number variable. And then add if statements for each random number how many you want.

Code:
on *:TEXT:hello:#: {
    var %rand = $rand(1,how many you want)
    
    if ( %rand == 1  ) {
       //do something
    }

    if( %rand == 2 ) {
      //do something
    }
    
   // and so on
}