Hi franklin,
While you cannot store a .pp7 into a .pp7(this would most likely require a major rethinking of PlanetPress, and it's VERY unlikely to be ever implemented), you can create a .pp7 with multiple conditional pages, and have PlanetPress pick the correct page to use based on a condition. So you could have 20 pages in the same document, each with their own logic and functionalities, and put a condition on them so that it picks the correct one based on the data. This is probably the best way to go, if you don't want to maintain multiple documents.
Regards,
Raphaël Lalonde Lefebvre