I don't know of a way to do exactly what you want. You can make a stacked note with a hex border, and that would at least make it easier to move each symbol around. However the horizontal line in the middle is thick and doesn't extend all the way across the hex, so you might not like it. You would also still need to manually align it with the leaders. I just thought I'd throw it out there in case you find it useful.
Actually I just thought of a way to keep the alignment. You can create a series of ordinate dimensions for each location of a tie-in point. Then you can change the dimension text to put the stacked note I described before. This would be accomplished with by entering the following into the dimension text box: