Narow down the network list / floating IP list

After a bit of research it seems there is a way to narrow down the network list / floating IP pool list to make users life a bit easier.
- The plugin should offer only private networks connected to a public network via router (for instance boot).
- The plugin should offer only public networks connected to selected private network via router (for floating IP association).

In case someone relies on a different combination for some use-case I do not see, I would like to hear before it gets implemented.