Using Extra Packages and Slinky post install scripts.
To add Midnight Commander to the slinky install place these three
files in the second_stage_scripts directory of slinky disk 2.
extra_packages
mc-4.5.51-36.i386.rpm.post.sh
mc.menu
Slinky reads the extra_packages file which contains just the name of
the Midnight Commander rpm file on Redhat CD 1, mc-4.5.51-
36.i386.rpm.
After it installs Midnight Commander it finds the post install script
and runs it. (Slinky also tests for pre install scripts)