$ tar -tvf pkg-groups.tar  | wc -l
92

pkg-groups specific on version distributive and not needed customization. However, you can set specific pkg list/group to install on autoinstall.scm (section /pkg-install) Its like software patterns on Yast or packages on Kickstart. 
As solution i use media_get_content() for delivery this file.

use snippet how, what for?