Similar to the Blocks in Rhino and many other programs.
Some mockup I made
1. Linked input
One object from the document could be used as an input for many VA GH Style Objects. Moving the VA Object would not move the curve of course.
You can think about it this way: You have many rectangle windows which number or sizes can change, but all of them are affected by one external curve, which splits the glass into two pieces on every window it crosses.
2. Embedded input
There is VA Object and a Curve input. Curve at the start can be Linked, but when you Embed it, then it is „internalized” (as in Grasshopper) and moves with and controls given VA Element.
You can still access this internalized Curve and modify it – it can work sort of like a widget.
Referencing this internalized curve by other objects maybe could be done, and beneficial, but for simplicity, I don’t write about it now.