Adding significance star on VBAR in SGPLOT

[lokerick]

Hello,

I'm attempting to avoid my instinct to switch to R when doing something graphical. Is there a way to add a significance star, p-value and/or connector above my clustered vertical bars to show a statistical difference between groups? 

Current code: 

proc sgplot data=cog_long;
	where test = "Rivermead";
	styleattrs datacolors=(%RGB(217,217,217) %RGB(127,127,127));
	vbar testnum / response=score stat=mean limitstat=stderr
		limitattrs=(color=black) group=trt groupdisplay=cluster
		nooutline;
	xaxis valueattrs=(size=12pt family="Times New Roman") 
		labelattrs  =(size=14pt family="Times New Roman");
	yaxis min=0 max=25 valueattrs=(size=14pt family="Times New Roman") 
		labelattrs=(size=14pt family="Times New Roman");
	keylegend / titleattrs=(size=14pt family="Times New Roman") 
		valueattrs=(size=14pt family="Times New Roman");
	title;
run;

Current graph: 

Note: significance star/connector would go above Memory Retention

The desired graph would have connecting line with ** above the Memory Retention tests similar to this graph produced in R:

[Ksharp]

You could use

BARPARM  statement + SCATTER statement (plot a big Star symbol)