There is a utility to customize the menu.ini file. It's called Notepad.
Check out how easy this is:
Step 1: Open Notepad.
Step 2: Open menu.ini (although ini files should already be associated with notepad, so you can probably simplify those 2 steps by double-clicking the menu.ini file)
Step 3: Add your item in whatever group you want, or create a new group for it. For example:
Section "Emulators"
{
Item "Sega Genesis Emulator","e:\emulators\dgenx\default.xbe"
}
You can change the name or the path to reflect where your game/app/emu is located.
Step 4: Repeat as necessary