Grouping columns in Matrix

Hello everyone

Currently I have a Matrix which looks like this:

Now I'd like to group the current columns to achieve this output:

Is there an easy / best way to do this?

The current source table looks like this:

The only solution I've found to achieve my goal is to unpivot the original table:

And to configure the matrix like this:

But I don't want to modify the structure of the original table because this will impact all my other visuals.

Thank you in advance for any hints.

Best regards,
PBI-Enthusiast