By the way, after a little effort, I found out that the idea with EventDrop also works. But the reference to the group has to be calculated through the ID() function. That is, to get a "Sheet.4" link, you will have to write "Sheet."&ID()
Then the formula for the end point will look like
EventDrop = SETF(GetRef(Sheet.7!PinX),"PNTX(POINTALONGPATH(Sheet."&ID()&"!Geometry1.Path,Sheet."&ID()&"!User.Label_B_Distance))")
+SETF(GetRef(Sheet.7!PinY),"PNTY(POINTALONGPATH(Sheet."&ID()&"!Geometry1.Path,Sheet."&ID()&"!User.Label_B_Distance))")
Two more SETFs will have to be added to serve the begin point of the connector. I'm not going to write this so as not to confuse readers

In the attached .vsdx file, this is implemented in the "drop" master.
---
This is the method that I suggested at the very beginning, referring to the article. But the example in the article is designed for a permanent reference like TheDoc, and in this case the reference should lead to a group. And the name of the group changes when the master is copied to the drawing page. But the inheritance mechanism does not take this into account in the POINTALONGPATH function argument. Therefore, we have to calculate the name yourself using the ID() function.