Here’s the basic idea of how to split an edge into N equal-length new edges. Notice how I work backwards (in the sense that my split ratio decreases). That way I don’t know have to know (or care) about the new edges. I just keep splitting the same edge, whose EdgeIndex I already know.

Based on that observation, here’s a rough draft of an ICE tree that takes an edge of length N, and splits it into N equal-length edges.