Heatmap Chart (URGENT help needed!)

Hey everyone.

I'm trying to build a heatmap for Risk Management purposes. The datasheet is pretty much straightforward (attached a sample).

The graph feeds from columns Risk ID and Risk Factor, which is a calculation between columns Probability x Impact.

What I intend to do is use a X Y Scatter graph and populate the Risk Factors, and each of them have the Risk ID as a label (please see attached sample).

PROBLEM: I can't get the Risk factors to overlap, which a want! So I have several Risk IDs with the same risk factor but they appear in different places on the graph. Since I'm using a gradient to represent the different heat areas, it is crucial for me that the several risk factors appear overlapped - of course when they have the same value!

Example: R2, R3 and R4, R8 and R9 ...

If you have any idea on how to solve this or even have a better solution for this kind of graph, please let me know.

Many thanks in advance.

Thanks
Antonio