for your purposes...
imagine a block that consists of something like a screw and a washer...
IF it is set to annotative you are free to insert it into the assembly, along with a block for the center mark (if not coming from the dimensions)
either way at a certain scale the centermark shows, however not the screw and washer because they would be meaningless or clutter at that scale.
at a smaller scale the screw and washer appear in the viewport and the centermark either does or is shown smaller because it too is annotative
either through the dimension string being annotative or the centermark block being so as well....
just to consider