Modular python admin pages
I ended up using Proxy models but will also try polymorphic approach. This is exactly what is designed to do, inherit models from a parent model in both one to many and many to many relationships.
I'm building a personal website that I need to apply modularity to it for purpose of learning. What it means is that there is a model that contains x number of classes with variations, as an example a button is a module that you can modify as much depending on provided attributes. I also have a pages model that need to select any of created modules and render it. I can't find any documentation of how to access multiple classes from one field to reference to. 
Model structure is as below:

Modules, contains module A and module B
Pages should be able to select any of module A and order its structure.

Please let me know if not clear, this is the simplest form I could describe. Am I confusing this with meta classes? How one to achieve what I'm trying to achieve?