Yes, I was looking for this before requesting. This would allow you to have 16 scenes in Scene mode and 8 in Hybrid mode!
If this is too complicated, in the meantime maybe they could change Hybrid mode so you could access the other row in this same way, toggling with the same switch. E.g. switch E toggles scene E and A, switch F toggles scene F and B, etc…
That would not require to double the amount of scenes per preset (if that is a bottleneck or difficulty here) and give a similar functionality in Hybrid mode.
But anyway, I agree with the OP, the secondary scene is the best solution here