You can also create more parent menu items (in addition to the advanced menu) and use the same concept as above. For example on the same level as the advanced menu, you can create an entry for WinOS setup pxe boot another one for disk utilities and a third for debug utilities. They don’t all have to be in one advanced menu.
You have to remember that you must be on the 1.3.0-rcX build (1.2.0 will not have the utiltiies to manage the iPXE menus from the GUI) and your paste into the parameters field must be a complete iPXE menu, so you must learn iPXE menu design (or find one you can hack up to your needs /like above/. http://ipxe.org/examples