Controlling the amount of horizontal jitter/offset for a stacked bar graph

A bargraph with stacked/grouped bars will have the horizontal positions of these bars slightly offset from their standard indices, e.g. a bit below and a bit above 1, same for 2, etc.

I know from this past thread that it is possible to find out how much that horizontal displacement/offset/jitter is. But is it possible to also control its size for an existing bar graph, i.e. not just find out how much it is?

It appears to not be possible to directly assign a value to hBar.XOffset, at least in R2016a!