Plotting both within and between groups differences

I am using ggpubr currently to plot my values. Thanks to the facets I managed to create subplots according to some factor. Finally, using the function stat_compare_means() I managed to plot only the differences between groups.

The minimal code to produce my figures is

library(ggpubr)

data("ToothGrowth")

my_comparisons <- list( c("0.5", "1"), c("1", "2"), c("0.5", "2") )

p <- ggboxplot(ToothGrowth, x = "dose", y = "len",
               color = "supp", palette = "npg",
               add = "jitter",
               facet.by = "supp", short.panel.labs = FALSE)
p + stat_compare_means(comparisons = my_comparisons, label = "p.signif")

where supp is the grouping factor, len the outcome and dose the independent variable.

This is the result:

I would like to display also differences within groups (e.g. statistical significance between 0.5|OJ and 0.5|VC), but I think it is not possible with my current code.

Could someone please point me towards some example on how to achieve what I want?