Conditional Format Dates in a Matrix Based on Values From Another Table

Okay, so consider "Windfarm A". I have a years' worth of KPI results, and they have been given a RAG status based on the value using conditional formatting - thats fine.

But Windfarm A's contract did not start until May 2019. I want to be able to highlight this fact on the timeline of the liner matrix, i.e. somehow highlight this month.

But this month is paticular to Windfarm A only. I have an additional table that holds all the contract start months.

So, each Windfarm could theorietically have a different contract start month that has to be highlighted at the appropriate point on the timeline/matix, whilst still retaining the RAG conditional formating.

I don't mind, in the example above, if the KPI for Windfarm A in May 2019 loses the RAG and is just a different colour.

Hope this illustrates that challenge a bit more? Thanks for getting back to me. 🙂