The new feature should place level data into the dependency graph data during the build.

Then at analysis time it can quickly get the level for a given node or get all nodes in a given level.

Possible Algos:
This can be done by using topological sort generator on the non private link graph, using the first node as a starting point or level 0, then walk the graph in both directions keeping track of +/- level and what nodes have already been visited.