Generating random points stratified by category within sampling hexagons using ArcGIS for Desktop?

I am trying to use two different layers together to generate a layer of random points that represent sample sites. The two layers are:

1. A grid layer of hexagon-shaped polygons created using the [Create Hexagon Tessellation][1] tool.
2. A polygon layer with four categories of percent impervious surface (%IS), created by reclassifying the NLCD %IS raster layer and converting to a vector polygon layer. Let’s say the categories are 0-25%, 25-50%, 50-75%, and 75-100%.

I would like to generate 25 random points for each category of %IS (100 points total), but only one point per hexagon. So 25 hexagons that have a point placed within a %IS polygon representing 0-25%, 25 hexagons that have a point placed within a %IS polygon representing 25-50%, etc.

I have tried using the built-in Create Random Points tool, the [GME Generate Stratified Random Points tool][1], and the Sampling Design Tool. However, I have only been able to create either

1. a points layer with one random point inside each hexagon but not associated with the %IS information (Create Random Points), or

2. a points layer where the points are stratified correctly by %IS but not constrained by the hexagon layer (GME, Sampling Design Tool).

Is there a way to do what I’m attempting?

Here’s an example of what a small portion looks like. The colors of the %IS polygon layer represent the four different classes (increasing %IS from blue to red).