Figured it out.
goto ${username} || goto MENU
:fogUser
menu
item --gap -- ---------------- Welcome fogUser ----------------
item return return to previous menu
item kav Kaspersky Antivirus
choose --default return target && goto ${target}
:fogTech
item --gap -- ---------------- Welcome fogTech ----------------
item return return to previous menu
item Clonezilla Clonezilla ISO
item UBCD Ultimate Boot CD
item Hirens Hiren's Boot CD
item kav Kaspersky Antivirus
choose --default return target && goto ${target}
:MENU
menu
item --gap -- ---------------- iPXE boot menu ----------------
item return return to previous menu
choose --default return target && goto ${target}
Then just define the functions below the menu. fogTech and fogUser being different users that the menu accounts for and MENU being the default menu.
This was made apparent after looking at the advanced.php code presented here https://wiki.fogproject.org/wiki/index.php/Advanced_Boot_Menu_Configuration_options
Access to this menu can be granted without granting that user rights to the website by clicking the “Mobile/Quick Image Access Only?” toggle when creating the user.