Summary: How to show inverted filled triangle in the leader
Exact solution for this type of representation does not exist it seems, however a good idea is conveyed by Saiful Hailri stating the use of datum selection while defining gtol reference. This will club the reference with the control frame and the inverted triangle of datum can be shared for gtol control frame.
Another important point is that option gtol_datum has to be set as asme from default ansi.
I thank to all who replied to my post. All replies are here: