Intelligent Stencil shapes

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1. I want to create some shapes that will represent various applications/components in a system. 
2. Each shape will have custom properties, indicating the technologies that comprise the app/component, as well some financial info like cost to maintain it.
3. I want to create a legend or some kind of summary shape that will automatically tabulate, for .e.g calculate the total cost to maintain for all app/components on the drawing page.

a) how do I go by doing it? (while I'v seen simple stencil shape examples, but never seen interactive stencil shapes), b) Is there a good reference you can point me to?

Thank you.