Hi Matthew,
Thank you for your question! If you add a guide with its own prerequisites as a prerequisite to another guide, you will have the option to add that guide’s prerequisites as well, so what you’re asking is possible.
Have you published a new release of your General Process Guide since you added the prerequisites to it? Whenever a guide references another as a prerequisite guide, it will only use the most current release and ignores drafts. If the General Process Guide only includes prerequisites in the draft, those prerequisites will not be carried on to your Top Level Guide.