Waterfall y axis break on a ‘simple breakdown’ chart

so i have added a category to the breakdown/stacking which has made the waterfall chart become a ‘simple breakdown’ so there are items between each category showing the variance.  However I am now unable to add an axis break in the y axis .   i read online this is because there is more than one category?   can anyone suggest how t do this.  also i really need the opening balance and closing balance to be the same colour but not green/red like the variance items