Provide functionality similar to the custom vertex status providers that allow users to define the logic used to determine the vertex status (and color) in a script.

A simple use case is as follows:

• Multi-layer map, where only the vertices in the bottom layer correspond to nodes

• We want to status of the vertices in the upper layers to be calculated based on worst severity of a an alarm (generated by an event with a specific UEI) for all the "child" nodes of that vertex