How to create an install file containing embedded install files

A SIS file can include other SIS files. To do this, in the PKG file, include the name and location of the embedded install file(s), and their package UID(s), prefixed with the @ symbol. For instance:

IF NOT package(0xE8000097)
; install minimal.sis only if not already installed
@"minimal.sis", (0xE8000097)
endif

During installation of the embedding SIS file, minimal.sis is extracted and is installed, unless it has already been installed.