How i create a command to call a command?

In general, I already know and I managed to create a command that creates a Fireball using "/mkt fireball <strenght>", but I think I'm doing it the wrong way: My command is "/mkt", and I'm creating others using the first argument, like "fireball". Onwards I can create a "/mkt build <shape>", with "build" being the argument. I'm pretty sure this is wrong, and that there is a way to create a command from a better command, such as "/rftdim safedel <dimId>" from RFTools Dimensions. In short, I want to implement something similar to "/rftdim" in my mod, which after that I can call my command. This shortcut is easier for the player to find out where the commands come from.

In Main.java, i am using this to register:

@EventHandler
    public static void serverStarting(FMLServerStartingEvent event)
    {
        ModCommands.registerCommands(event);
    }

Herei i register:

public class ModCommands{
    public static void registerCommands(FMLServerStartingEvent event)
    {
        event.registerServerCommand(new BaseCommand());
    }
}

And here i use the first argument to call a command, like Fireball or Build:

public class BaseCommand extends CommandBase {
    @Override
    public String getCommandName() {
        return "mkt";
    }

    @Override
    public String getCommandUsage(ICommandSender sender) {
        return "/mkt <command>";
    }

    @Override
    public void execute(MinecraftServer server, ICommandSender sender, String[] args) throws CommandException {
        List<String> commands = new ArrayList<String>();
        commands.add("help");
        commands.add("fireball");

        if (args.length > 0) {
            if(args[0].equals("fireball")){
                new Fireball().execute(server, sender, args);
            }
        }
        else{
            String formatted = "";
            formatted += TextFormatting.BLUE;
            formatted += "/mkt help";

            String notFormated = "";
            notFormated += TextFormatting.WHITE;
            notFormated += "to help.";
            sender.addChatMessage(new TextComponentString(formatted + " " + notFormated));
        }
        if(args.length > 0) {
            if (!commands.contains(args[0])) {
                String formatted = "";
                formatted += TextFormatting.BLUE;
                formatted += "'" + args[0] + "'";

                String notFormated = "";
                notFormated += TextFormatting.WHITE;
                notFormated += "are not a Mekatronic command.";
                sender.addChatMessage(new TextComponentString(formatted + " " + notFormated));
            }
        }
    }
}

All my others command extends CommandBase, my BaseCommand  just decides which command to call.

I tried to find out in RFToolsDim's .jar how they implemented the commands, but I'm new to java, and I don't understand anything.