The idea is that I have a set of properties that represent possible options in the app. These options can be modified through a variety of different ways, such as from the UI, remotely, third party, etc...
Each time one of these modifiers alters the state, the other modifiers need to be notified. E.g.: If the user marks a checkbox in the UI, the remote modifier and the third party need to be notified, so that they update their internal state.
There is no priority involved, and the state changes cannot be rejected. The only concern is to prevent the third party from receiving a notification when itself modifies the state.
Is there a good design pattern to solve these requirments?