[Fedora-packaging] Customizing Fedora Installer

Hi, I'm trying to customize the Fedora installer for my orgs use. The idea is we have apps that we want to include in the fedora cd/dvd installer, we only need it for our own, not for the whole fedora distribution. What I've tried so far is pungi, and yes, I was able to produce an updated installer. the only problem that i have now is i dont know which files to modify to add our app in the package selection can someone point me to a document that i should read to carry out our plan? or is this really possible? Thank you very much in advance. Best regards, Amir