How to remove the legendgrouptitle_text from the hovertemplate when hovermode is xunified?


I have a grouped stacked bar chart, as illustrated here: Grouped + Stacked Bar chart

Traces are on the same xaxis, and same yaxis

Each group (A, B C) has 4 stacked bars.

First, how can I get rid of the mention “group1” at the top of the x unified hover?
I found a lot of discussion about this, listed in a post here : Customizing text on x unified hovering - #19 by etonblue

Second, is there a way to get the spike line displayed on a specific group of stacked bar? Currently, there is one single dashed vertical line, above the group in the middle.
Third, it would be better to use a box plot for this, but is there a way to color the different segment of a box plot ?