I was thinking about this.

The cyan (red senstized) layer needs to use a sensitizing dye that is retained during the first developer so that the bottom (cyan) layer can be re-exposed to red light. Since all other dyes are designed to wash out, you need a very particular dye for the cyan layer that will not wash out until the silver is bleached away.

Getting this dye is going to be a major requirement for your project.